Friday, May 31, 2013

Cancer in Cats: Summary

Cancer in Cats: Summary

This month's blog posts have been awfully depressing, haven't they? Perhaps that's just for me, since I've had to research and write them all! But if you've been following them, you may also be worried about every little abnormality you notice in your cat.

That's not entirely without intent, and hopefully it hasn't deterred you from continuing to read the Old Maid Cat Lady blog. During May, which has been Pet Cancer Awareness Month, I wanted to make everyone aware of the many types of cancer that may strike their feline companions. In every instance, catching these cancers earlier rather than later means that your cat will have a better chance of surviving. Checking your cat at home helps you better bond with kitty, and enables you to ask your veterinarian about anything suspicious, as well as catching the early symptoms of any cancers that may be lurking.

Cancer is one of the leading causes of death in cats. Lymphoma and skin tumors are the most common. The good news is that cancer is almost always treatable if caught early enough. Pathologists examine a tumor to "stage" it, determining how far it has progressed. For all tumors, the standard staging system is:

  • Stage I means the tumor is a single growth that has not spread.
  • Stage II is a tumor that has spread locally, or it could be multiple tumors on the same side of the body.
  • Stage III would be a tumor that has begun spreading beyond its local area, or multiple tumors located on both sides of the body.
  • Stage IV tumors are metastasized (spread) too much to be treatable, and are considered fatal.

If you've missed any of this month's posts, there were eight types of cancer examined in great detail. They were:
Today's summary lists several other types of cancers that may attack your cat, but will not go into as much detail as the others.

Granular Cell Tumors 

These tumors are most often found in the mouth, but can also affect other parts of the body. In cats, they have been found on the tongue, tonsils, vulval area, brain, and toes. They are rare and may originate from nerve cells. Removing them surgically typically takes care of the problem.


Also known as sarcoid tumors, these are found more often in cats living in rural areas, possibly because of their relationship to the bovine (cow) papillomavirus. They are commonly found on the nose, lips, and ears, but can occur in other places.

These tumors' tendency to send little tendrils into adjoining tissue means that it's difficult to remove all of the tumor surgically. Better results are often obtained with cryosurgery (freezing), radiation, or amputation if the tumor is located on a cat's leg, tail, or ears.


This is a type of cancer that affects a cat's bones. It is more common in older cats, and more commonly seen on rear legs than on front legs. It is also often found in the mouth. Its cause is unknown, but it has been found on the site of a previous break in a leg. 16% of cases tend to be malignant. Surgery to amputate the affected area typically allows the cat to live a normal lifespan.


This is another type of oral cancer that affects cats. At one time it was known in the medical field as acanthomatous epulis. It may occur in the jaw or on the gums, and is most often benign. 

Inductive Fibroameloblastomas 

This type of tumor is only found in cats, and originates in the connective tissue. Its uniqueness within felines is likely why so few studies have been done on this type of cancer. It commonly occurs on the front part of the upper jaw. 

Basal Cell Carcinoma 

These are the most common types of skin tumors in cats. They may be benign or malignant.

A basal cell tumor may appear as a pigmented, ulcerated nodule, like a sore. Typically, the tumor has no hair on it.  One can appear almost anywhere on your cat's body, but it is most commonly in the head, neck, or shoulder area.

While most basal cell carcinomas are benign, they do require surgical removal, and the earlier the better. This typically takes care of the problem and no radiation or chemotherapy is necessary. Most cats recover completely.

Hepatic Neoplasia 

This is the medical term for liver cancer. Older cats are more prone to it, and male cats more so than female. It will cause the cat's abdomen to bloat. Your cat may breathe quickly or have difficulty breathing. You may notice a yellow, jaundiced look to his skin or the whites of his eyes, and pale gums from anemia. As with most cats who feel sick, he'll have a poor appetite, perhaps vomit (don't all cats?), and lose weight.

Quick action is necessary to save your cat's life. Other diseases can mimic the symptoms of liver cancer, and many other types of cancer can spread to the liver.  Some types of these tumors can be removed surgically. If not, the cat may be provided with palliative care until the cancer claims him.

Mammary Neoplasia 

This is a cat's equivalent of breast cancer. It is the third most common type of tumor in cats, but is almost unheard of in spayed females. Older cats that have been bred are most susceptible to it, with the Siamese breed at twice the risk of other breeds. Many of these tumors will occur on the cat's front (anterior) mammary glands rather than the rear (posterior) ones. Most require surgical extraction, with early identification and treatment greatly improving the cat's chances of survival. There was a prior post on the Old Maid Cat Lady blog about feline mammary cancer, one year during Breast Cancer Awareness Month. Click on the link in the previous sentence to read it.

Yes, these are a lot of types of cancer, and yes, there are many more. Now you can probably understand why some veterinarians (veterinary oncologists) specialize in diagnosing and treating cancer! And if these posts can save one life, or spare one cat from enduring advanced forms of cancer by allowing that cat's owner to identify his (or her) cancer earlier, it will have been worth all the depressing work to research, write, and publish this series.

I promise that future posts will get back to fun subjects and telling you all about the wonderful products on! And hopefully this series has done some good for Pet Cancer Awareness Month. Thanks for sticking with me through it!

Thursday, May 30, 2013

Cancer in Cats: Melanoma

Cancer in Cats: Melanoma

The Pet Cancer Awareness Month series continues with a look at melanoma in cats.

Melanoma is so named because of its connection with the melanin that produces pigment in the skin, hair, and eyes. If not identified early and treated, it can spread widely to affect the cat internally.

But melanoma doesn't just appear on the skin. It can affect the ears, mouth, toes, and eyes, as well. In fact, melanoma is the most common type of tumor that occurs in a cat's eyes. Here's the rundown on it:

Feline Melanoma

In a healthy cat, melanocytes are the cells responsible for producing melanin, or pigment, in the cat's skin, coat, and eyes.

Abnormal growth of these cells that is not cancerous (benign) is often called melanocytoma. This is the non-spreading form. You will often see these as little black spots on the lips, eyelids, nose, and gums of cats who have orange (red), cream, or silver colored coats. Only if they start to develop further should you be concerned.

When it becomes malignant, melanoma starts to spread (metastasize). Many refer to this form as malignant melanoma. It is rare in cats, but not unheard of. Locally growing at first, melanoma eventually will invade the lymph nodes and spread to other areas of the body. The internal organs most commonly affected are the lungs, but it can spread to any part of the body.

Melanoma accounts for less than 2% of feline tumors altogether, less than 1% of feline oral tumors, and 0.5% of skin (dermal) tumors in cats. Ocular melanomas (those in the eye) are more common than oral or dermal locations. Oral melanoma is much less common in cats than it is in dogs. Oral and ocular melanomas are typically more malignant than are the dermal variety, as well.

Symptoms of Melanoma in Cats

Symptoms vary depending on the location of the melanoma tumor.

In the eye, the tumor will most often appear in the iris of the cat's eye. These are commonly referred to as "iris spots" and cause the iris to thicken or appear irregularly shaped. Your cat's eyes may even start to look a different color. Some melanomas may appear as a dark spot at the point where the white of the eye touches the iris. They can grow on the surface or the interior of the eyeball.

With ocular melanoma, you may first notice the cat's eye appearing red and tearing (weeping) more than normal. It may be painful, and your cat may paw at it as well as cry out or pull away when you try to touch it.

If left untreated, the cat can develop glaucoma in the affected eye. The pupil will become dilated and the eye may bulge. This will eventually cause blindness.

With the dermal variety of melanoma, you may first see little black bumps on your cat's skin, in locations like the ears, nose, back of the head, tail, toes, back, or eyelids. These could be benign melanocytoma growths...or not.

Look for a single, dark-colored growth that is usually raised. Dermal melanoma may also be seen on the scrotum in un-neutered tomcats.

If in the mouth (quite rare in cats), the cat may have bad breath and drooling. There may be some bleeding from the tumor itself. The face may swell and the cat could have a hard time eating.

The tumor may ulcerate and bleed. It may look velvety. The fur around it may fall out as it will be itchy and your cat may lick or scratch it a lot. This can also make the skin around it red and swollen.

Once melanoma has spread to the lungs, the cat may have difficulty breathing.

Cats who are middle-aged (ages 6-14 years) or older have a greater likelihood of showing symptoms of melanoma, especially those affecting the eyes. Cats that are "heavily pigmented" or dark in color, according to some sources, have a higher risk for melanoma. Other sources say that white cats are more prone to it. 

Hairless cats such as the Rex and Sphynx breeds are also prone to melanoma, with no coat to protect their skin from sun exposure. Of course, the growths are also more readily apparent on these cats, so they're easier to catch early.

It's important to remember that not all melanoma tumors are pigmented, and not all dark tumors are melanomas. So if you find a suspicious growth that seems to fit the above symptom descriptions, a trip to your veterinarian is necessary to address the problem early.

Diagnosing Melanoma in Cats

Make notes on the symptoms you have observed and when you noticed them, as well as on your cat's general health and eating habits. This will be important information for your veterinarian to have when making a diagnosis.

Your vet will draw blood and take a urine sample from your cat for analysis. An X-ray of the chest area will show whether any cancer has spread to the lungs. A needle biopsy of the tumor itself may be done. Often a sample is also taken from the nearby lymph nodes, as well. 

If the growth is located on the rear legs, an ultrasound may be performed on the abdomen. 

If the tumor is in the eye, an ophthalmoscope or slit-lamp biomicroscope can often be used to see it. A gonioscope may be used to measure the eye's internal structure for indications that the tumor is spreading. You may be referred to a veterinary ophthalmologist for this. A tissue sample will be required to confirm that the tumor is melanoma by viewing the cells under a microscope. This may be done via needle biopsy, surgical biopsy, or complete removal of the eye, depending on the size and location of the tumor.

There are three different types of melanoma that can affect a cat's eyeball itself:
  • Primary conjunctival tumors:  cause pain, redness and weeping.
  • Limbal tumors: cause black nodules protruding from where the cornea meets the white of the eye.
  • Iris diffuse melanomas (iris spots, iris freckles): cause a thickening and discoloration of the iris.
The tissue samples taken from the suspicious tumor must be sent to a lab for analysis. Included in the pathologist's report will be not only a diagnosis of the type of tumor, but the growth rate of the cancer cells. This is important in determining how far along the cancer has progressed (also known as "staging"). According to the World Health Organization's staging system for tumors, a Stage I melanoma would be smaller than 2 centimeters in diameter. Stage II: 2-4 cm. Stage III: 4 cm or larger. Stage IV: any size tumor with evidence of spreading (metastasis).

Treatment for Melanoma in Cats

As with most tumors, surgical removal is usually the first course of treatment. If the melanoma is on the cat's toe or the bed of the claw, that toe will likely be removed. In an older cat where the disease is progressing slowly, it may be kinder to take a "wait and see" attitude rather than subjecting the cat to radical surgery.

Melanomas in the mouth often require removal of a large section of the jaw to make sure all of the tumor is removed.

Depending on the type, location, and size of melanoma in the eye, laser surgery can be used to destroy a small tumor. This would be the preferable option, as it may be possible to destroy the tumor without the cat needing to lose the entire eye.

If the tumor is on the iris and is identified early, many veterinary ophthalmologists take a conservative approach to observe the tumor's growth on frequent visits. Only if the melanoma is growing or if there is a concern about the cancer spreading will surgery be done. When surgery is used, the entire eye is commonly removed. Surgery will always be chosen if the iris is noticeably changed by the melanoma. No radiation or chemo are typically used with melanomas in the eye.

Chemotherapy may also be used if the tumor could not be completely removed by surgery, although some sources have found melanoma resistant to it so the results have been disappointing. Some vets may recommend radiation therapy in some cases.

Some dogs can benefit from immunotherapy with Ki-67, but this has not been used on cats. Some cat owners choose a homeopathic treatment, which traditional vets view as controversial.

Once the tumor is removed, your cat will typically need to wear a special collar to keep from irritating the surgical site. The incision site needs to be kept clean and dry. Report any changes in this site or delays in healing to your vet. With tumors removed from the eye, there will likely be eye drops or ointments that must be given to fight infection and reduce swelling.

You'll need to keep a diligent watch on your cat after removal of a melanoma, as another could appear. Pay close attention to the site of the surgery, just in case any cancer cells remain there. Tumors affecting the eyes can lead to glaucoma over several years that will eventually force removal of the eye. They require semi-annual checkups with your vet to make sure this is not happening.

Prognosis for Cats with Melanoma

A lot of this depends on the report from the pathologist at the lab when the tumor's cell sample is sent for analysis. Melanoma tends to be more malignant in cats than it is in dogs. And in cats, this type of cancer behaves more like melanoma in humans.

The size of the tumor is one factor in determining a cat's prognosis with melanoma. If caught in Stage I and treated, the cat may live a normal life afterward.

A cat's prognosis is also related to where the melanoma appears. Melanomas in the eye are the most often malignant, but removal of the eye may stop any progression of the disease. Oral malignant melanoma has an average survival rate of around two months. Malignant melanomas on the skin give a cat four to five months after surgical removal.

Melanomas found on the eyelid, eye, scrotum, toe, or in the mouth are more often malignant than in other locations. One estimate puts the percentage of oral melanomas being malignant at 60%, another at about 50%. On the claw bed, 30% to 60% of them are malignant, those figures including dogs as well as cats. Iris spots are said to metastasize about 20% of the time. On the skin, 53% to 71% of tumors are malignant melanoma.

Once the melanoma metastasizes (spreads), the prognosis is more guarded. This can occur without being noticeable on X-rays, and without blood work showing it. Even with radiation therapy used after surgery, a melanoma that has already metastasized will return around 67% of the time.

In any event, once melanoma is diagnosed and treated in your cat, you'll be visiting the vet about every three months for follow-ups. X-rays will likely be taken twice a year to check for any spreading of the cancer.

Preventing Melanoma in Your Cat

Sun exposure is a common cause of melanoma in humans, and it may also be a cause of melanoma on a cat's ears, nose, and other places where the coat is thinner or white. So keeping your cat out of the sun may help prevent it, especially if your cat is among the higher-risk groups. If your cat's favorite thing is to bask in a sunny window all afternoon, put a UV-blocking tint on that window. If your cat is going outdoors, use a pet sunscreen.

But the causes of melanoma are not widely researched in cats. One study reported that experiments had produced melanoma in cats by injecting a particular strain of feline fibrosarcoma virus. There does not appear to be any predisposition to developing melanoma among any particular breeds, nor any strong correlation with age, sex, or coat length.

Veterinary oncologists have been using an enzyme called tyrosinase as a sort of "vaccine" against melanoma in dogs. However, this therapy has not been extended to include cats.

As with all types of cancer, the earlier the tumor can be identified and treated, the better. So keep a close watch on your cat, do frequent physical exams disguised as cuddle sessions, and make note (in writing, including the date) of anything out of the ordinary so you can mention it to your veterinarian.

Sources: "Skin Cancer in Cats: Types and Treatments", WebMD; "Malignant Melanoma in Cats", Dr. Bari Spielman, Pet Place; "Eye Tumors - Melanoma in Cats", VCA Animal Hospitals; "Malignant Melanoma in White Cats", Vet Pet MD; "Iris Melanoma in Cats",; "Melanomas in Dogs and Cats", Webvet; "Malignant Melanoma", Wendy C. Brooks, DVM, DipABVP, The Pet Health Library; "Skin: melanoma", Dr. Philip K. Nicholls and Dr. Marion O'Leary, Vetstream; "Feline Melanoma: A Comparative Study of Ocular, Oral, and Dermal Neoplasms", A.K. Patnaik and S. Mooney, Veterinary Pathology Online; "Tumor of the Eye in Cats", Pet MD; "Melanoma", Vetbook.

Monday, May 27, 2013

Cancer in Cats: Hemangiosarcoma

Cancer in Cats: Hemangiosarcoma

The series for Pet Cancer Awareness Month continues with a look at hemangiosarcoma. First the good news: this is a much rarer cancer in cats than it is in dogs, representing only about 2% of all feline cancers. The bad news is that unless it's the skin form of the disease, it's not a diagnosis you want to hear.

What is Hemangiosarcoma?

In a healthy cat, there are cells lining all the blood vessels in the body. They are called endothelial cells. These cells help the blood to flow smoothly through the body.

Hemangiosarcoma is a malignant tumor affecting the endothelial cells. It is sometimes called HSA. The tumors that form as a result of it tend to be blood-filled and prone to rupturing. It can occur anywhere in the body, since the blood vessels are everywhere.

There are four forms of HSA in cats. One affects the skin (Dermal). The second attacks the area just under the skin (Subcutaneous or Hypodermal), although some experts group this type together with the dermal form, referring to them both as Cutaneous. Another affects the internal organs (Visceral) and is the most rare in cats. The fourth form is found in the mouth (Oral). HSAs can also occur on the bones, although this is usually due to their having spread from the primary location.

The dermal and subcutaneous forms of hemangiosarcoma are the most common in cats. They are often located on the cat's head or rear legs. About half of the HSAs diagnosed are of these forms.

Subcutaneous tumors spread to other areas of the body about 60% of the time. Often, hemangiosarcoma spreads to the lungs. Spreading is rapid and causes bad internal bleeding that can be life-threatening.

If on the heart, bleeding will cause blood to fill up the sac surrounding the heart (pericardium) so that the cat's heart will not have room for the blood flowing through it.

In cats, the visceral form of hemangiosarcoma can also occur in the intestines, which also have a lining of endothelial cells.

When it spreads to the bones, hemangiosarcoma can affect the spine, pelvis, skull, and legs.

What Causes Hemangiosarcoma?

Because this type of cancer is so rare in cats, little research has been done on it other than anecdotal observations. Many vets may even be unfamiliar with it. Sun exposure may be a factor in the development of the dermal and subcutaneous forms. Cats with thin or lighter-colored coats would be more at risk for this if they spend a long time basking in the sun.

Older cats seem more likely to get this type of cancer, although keep in mind that it is rare in cats compared to dogs. There has been no determination of a correlation between HSA and any particular breed of cat.

Although causes of it in cats are unknown (other than the connection with sun exposure), in humans it can be caused by exposure to certain chemicals. As with most types of cancer, it's likely a combination of factors, both environmental and genetic, as well as viral exposure, that come together in the perfect storm for an individual cat.

What Symptoms Would I Look For?

Your cat may have a dark red, purple, or bluish-black raised nodule on the skin, more commonly on the head or the back legs or paws. Have your vet test it quickly, as the dermal form can quickly metastasize (spread) internally if not removed.

If the tumor is subcutaneous, the skin on top of it may look completely normal. You may see some swelling that appears firm and soft, but moves (because it is filled with blood) when you touch it. The skin may look bruised over the swollen area. It may pop up fairly quickly.

In the spleen, you likely wouldn't notice much unless your cat's abdomen is distended from an unusually large tumor. There may be vomiting and diarrhea. Your cat may be lethargic or refrain from vigorous play.

As the cancer grows, your cat may hide more. Kitty may pant or gasp for breath, or seem to have difficulty breathing. The cat may seem confused or "out of it". The gums may be pale from anemia.

If the tumor is in the spleen or the heart, it can rupture and bleed profusely, even if benign. This is a life-threatening situation. The sudden collapse of your cat due to this internal bleeding may be the first symptom you see. The cat may be crying from pain at this point. Emergency veterinary care is required in these cases, and may still not save your cat's life.

Oral hemangiosarcoma tumors would usually appear on the gums. There will likely be a loss of appetite accompanied by weight loss as eating becomes more painful and the cat feels worse.

If the cancer has spread to your cat's bones, the cat may limp. You may notice a swelling in a leg or near any bone. The cat may break a bone for no apparent reason. Or you may notice bleeding as the first symptom.

How is Hemangiosarcoma Diagnosed?

Make notes on any of the above symptoms you notice, including when you notice them, so that you can give your veterinarian the most complete information possible.

In addition to performing a thorough physical exam on the cat, your vet will need to take some of kitty's blood and urine for testing. An X-ray or ultrasound of the chest and abdomen will be taken. If the abdomen is swollen, some of the fluid will be drawn for analysis. An EKG (electrocardiogram) may be done to check the heart rhythm. A sample of tissue from the tumor will be taken for biopsy.

The forms of the cancer affecting the heart and spleen can only be seen on X-rays. The heart will appear round on the image, as all that can be seen is the blood-filled sac around it. Some of the pericardial fluid may be drawn for analysis.

Even with the dermal form of this cancer, imaging may be done on the lungs, abdomen, and heart to check for signs that the cancer has spread to those areas. This is especially important for the subcutaneous tumors, as they are often not discovered as early.

How Are the Dermal and Subcutaneous Forms of Hemangiosarcoma Treated?

Skin tumors are removed surgically. A biopsy will be done on the tissue that's removed to make sure all of the tumor was extracted. There may also be a few months of weekly chemotherapy to make sure all the cells are killed. The chemo will probably make your cat's coat fall out in places or change color, and will make him feel bad after each session. There may be behavioral changes resulting from the cat's discomfort during this time.

Especially with subcutaneous tumors, complete removal is often difficult. Radiation may be used on these sites. Once treated, monitor your cat closely with frequent vet visits to make sure the cancer does not return.

It is important to seek treatment quickly. In addition to being quite volatile and subject to rupture, these bloody tumors spread quickly and will become fatal within a very short timeframe.

After surgery, make sure your cat is on a high-quality diet. This will give the cat's body the appropriate nutrients to recover from the surgery and remain stronger during chemo. You may need to syringe-feed the cat if he won't eat. The vet may prescribe medication for pain, which should be given with great care to avoid overdosing the cat. Kitty will need a quiet, calm place to heal after surgery and may need a special collar to keep him from licking or scratching at the wound. Keep your cat out of the sun or get a coating put on your sunny windows that includes a UV blocking tint.

If the cancer returns, whether in the same or another location, your cat may need multiple surgeries, one for each recurrence. Eventually, one of these may claim your cat's life.

How Are Other Forms of Hemangiosarcoma Treated?

In about 30% of cats, visceral HSA (the one affecting the body's major organs) is not discovered until it is too late to be treated and the cat must be euthanized when diagnosed. Or the diagnosis may not even be possible until after the cat's death, during an autopsy.

A tumor on the heart will be discovered in an emergency situation. The blood in the pericardium must be removed with a needle to save your cat's life. The first course of treatment is to stabilize your cat, who will likely be in shock.

Most of these tumors will already have spread by the time they are discovered. If the tumor can be surgically removed, chemotherapy will be used following surgery.

If the tumor is on the spleen, the cat's spleen must be removed. This is followed by chemotherapy.

What's My Cat's Prognosis With Hemangiosarcoma?

The visceral forms of hemangiosarcoma are commonly fatal, with the cat living less than a year after diagnosis.

For dermal and subcutaneous forms, try to find a vet who has personal experience with hemangiosarcoma in cats. Cats have a much better prognosis than dogs with these forms of the disease. Once the tumor is completely removed and if it has not metastasized, the cancer may be cured for a little while. This is much more the case with cats than it is with dogs. If removed completely, as determined by a biopsy of the removed tissue, the tumor should not grow back. It may have already spread without discovery, however, and crop up someplace else shortly afterward.

Subcutaneous tumors tend to recur about 60% of the time.  By itself, surgery provides a "median" survival time of 6 months, meaning that half of all cats treated lived longer than 6 months, while half did not live 6 months. Chemo is needed as a follow-up to surgery for best results.

If treatment is given for the visceral form and your cat survives it, hemangiosarcoma can go into temporary remission...the operative word there being "temporary". Surgery alone can give your cat around 4 months of additional life. Surgery with chemotherapy may give around 8 months of life (total, not on top of the 4 with surgery alone). The median survival time is 77 days. As stated earlier, this is not a diagnosis you want to hear. HSA is never completely cured.

To protect your cat from hemangiosarcoma, minimize kitty's exposure to the sun. You can get a clear film for your windows that filters UV rays; it'll have the added advantage of reducing fading of your floors and furniture! If your cat goes outdoors, make sure there is shade readily available. There's also sunscreen that can be applied to light-colored or hairless cats. Do not force your cat to go outside in the sun if he doesn't want to. Limit exposure to chemicals as much as possible (not an easy feat in our modern society). Beyond that, there's not much you can do.

Note: The image shown above this post is of a growth that appeared on my little Vixen's chin for the last few years of her life. A biopsy on it did not reveal any malignancy, but it would occasionally fill with blood and rupture, so I used it for the image associated with this type of cancer. It's not necessarily what a hemangiosarcoma looks like, but because they're so rare in cats, there aren't a lot of images of them.

Sources: "Hemangiosarcoma", Wendy C. Brooks, DVM, DipABVP, Veterinary Partner; "Hemangiosarcoma in Cats and Dogs", Lap of Love; "Hemangiosarcoma in Cats", Dr. Kimberly Cronin, Pet Place; "Hemangiosarcoma of the Bone in Cats", Dr. Jeffrey Philibert, Pet Place; "Skin Cancer (Hemangiosarcoma) in Cats", Pet MD; "Feline Hemangiosarcoma vs. Canine Hemangiosarcoma: Different for Cats Than Dogs", Melissa Nott, Yahoo! Voices; "Feline Subcutaneous Hemangiosarcoma: Joey's Story", Melissa Nott, Yahoo! Voices; "Hemangiosarcoma in cats: 53 cases (1992-2002)", National Institutes of Health; "Feline Hemangiosarcoma", Barbara Yarington, 910 Pets; "Hemangiosarcoma in Cats", Winn Feline Health; "Hemangiosarcoma in Cats and Dogs", Pet Cancer Center; "Research Update: How effective is surgical excision of feline cutaneous hemangiosarcomas?", Joseph Harari, MS, DVM, DACVS, DVM360.

Friday, May 24, 2013

Cancer in Cats: Chondrosarcoma

Cancer in Cats: Chondrosarcoma

The Pet Cancer Awareness Month series continues with a study of Chondrosarcoma, or CSA. This malignant type of cancer affects the cartilage between the bones and joints, and is rare in cats compared to many other types of cancer.

Depending on the type of chondrosarcoma, it may spread slowly or very rapidly. It's presently unknown what causes this type of cancer. This is partially because it is so unusual that there are not a lot of cases to study. A higher incidence of nasal CSAs among cats living in urban areas may indicate a link to air pollution. The type affecting bones has been found to contain viruses in the cells of the tumor, suggesting a viral connection. Some bone tumors develop on the site of a previous fracture, which may mean there's a link with the body's cells that heal a broken bone. But it's believed that several factors combine with each unique cat's physiology to cause the cells to become cancerous.

Connective tissue occurs throughout the body, so CSA tumors may affect your cat's nose, mouth, bones, or throat.

As the tumor grows, it will cause your cat's blood calcium levels to rise. This can also damage the kidneys.

Because this type of cancer is so aggressive, it can threaten your cat's life if the diagnosis is positive for it. These tumors may spread slowly or rapidly, depending upon where they are located. In any event, catching them early is key.

Types of Chondrosarcoma in Cats

Some chondrosarcomas are in the mouth. If located on the upper jaw, these can spread to the bones. They can also spread to the cat's lungs or lymph nodes.

Some types of chondrosarcomas are in the nasal cavity. They will affect the cat's breathing.

Some chondrosarcomas are in the throat. They involve the larynx and trachea.

Some chondrosarcomas affect the cartilage between the bones. These are also known as myxoid tumors. Around 70% of them affect bones in the head or body cavity, the remaining 30% bones in the limbs. Sometimes they grow in places where a bone has previously been broken. There are tumors that can develop on a cat's bones that are not cancerous, however. These are the result of abnormal development of cells in the cat's bones.

Symptoms of Chondrosarcoma in Cats

Oral chondrosarcomas may show up as a lump under the skin of the face, or in the mouth. The surface of the lump may be smooth or knotty. The cat's face may look deformed and some teeth may be loosened. There may be an ulcer on the cat's gums. The cat may drool, have bad breath, and find it difficult to eat, resulting in weight loss. The mouth may bleed. Sometimes the nearby lymph nodes will swell.

In the nasal cavity, these tumors may cause your cat to sneeze and have a hard time breathing. There may be a pus-like nasal discharge or nose bleeds. Your cat may "reverse sneeze," inhaling through the nose and then making a gagging or snorting sound as though choking or trying to clear mucous from the throat (paroxysmal respiration). The cat's eyes may produce more tears. On the side where the tumor is located, the cat's eye may bulge.

Nasal cancer will typically start on one side of your cat's face, and may spread to the other if not addressed soon enough. If it continues to spread, it will eventually affect the brain and cause seizures. The symptoms of some bacterial infections can mimic those of CSAs, so don't become too alarmed until your vet does testing. Oral CSAs spread quite slowly.

In the throat, you would notice a change in your cat's voice, and kitty may lose his purr. Breathing may be noisy or sound "harsh" and may be quite difficult for your cat, who may actually breathe with his mouth open. When exercising, kitty may tire easily or suddenly collapse. The mucous membranes may have a bluish cast to them. The cat will likely have difficulty eating because it's hard to swallow. 

Bone CSAs are another matter; they spread relatively quickly. If it's affecting one of the cat's legs, there may be swelling at the location of the tumor. The swollen area would be hard when you touch it. If the tumor is in the pelvic area, the cat may have trouble using the potty. Despite straining to go, there may be little pee or poop that comes out. The affected leg will likely be painful to the touch and the cat may limp or become lame. Sometimes this lameness is the first symptom you will notice. The affected leg may be hot, as though feverish. The bone may even fracture.

Chondrosarcomas targeting the bones metastasize (spread) rapidly, and other symptoms may show up depending on which part of the body it has invaded. In about 10% of cases, they spread to the lungs.

Some studies say that older cats are more susceptible to CSAs, but cats of any age can get them. Other sources say that they're more common in middle aged cats. Male cats who are neutered appear to run a slightly higher risk, as do Siamese cats. But other studies have found no connection to the cats' sex or breed. In one study of 67 cats, males were twice as likely as females to have this type of cancer. As stated above, the nasal form shows up more often in cats that live in urban areas than it does in those living in the country.

Diagnosing Chondrosarcoma in Cats

Make notes on the symptoms you observe at home, including when you noticed them, to tell your veterinarian. After a physical exam, the vet will take blood and urine samples and needle-biopsy a tissue sample from the cat's lymph nodes to be tested. These samples will need to be sent to a specialized lab for a veterinary pathologist to examine.

X-rays, CT scans, MRIs, endoscopies, rhinotomy, or other types of scans can reveal where the cancer has invaded. The suspected area is often biopsied for further analysis in a lab. The tissue sample will go all the way to the bone. For suspected throat cancer, a bronchoscopy may be ordered. For oral cancer, an endoscopy.

Treatment for Chondrosarcoma in Cats

Surgical removal of these tumors is the only truly effective method of treating them. If a leg is affected and the cancer has not spread anywhere else, the leg is normally amputated to save the cat's life. Most cats can function quite well with only three, or even two, legs.

In the rib area, the affected rib may be surgically removed, along with nearby connective tissues, and even a portion of the lung to make sure all cancer cells are removed.

Tumors on a cat's jaw (upper or lower) are also removed surgically, which may be quite disturbing to see, when most of your cat's jaw has been removed. For tumors in the nasal cavity, often radiation is the only real option for treatment. Tumors in this location cannot usually be removed by surgery.

For throat tumors, the portion of the trachea affected by the tumor must be removed, along with surrounding tissue. The surgeon will try to save the cat's larynx, if at all possible. Radiation is not typically used with surgery for these types of tumors.

If the cancer has spread to more locations than can be surgically removed, radiation is also used to treat those.

Chemotherapy may be used supplementally with surgery or radiation, but has not been tested for its effectiveness on its own. Because of its toxicity and cats' sensitivity, it is not typically used. Radiation is sometimes useful after surgery to kill any remaining cancer cells and minimize the chance of recurrence.

During recovery, the vet may put your cat on an antibiotic to prevent any secondary infections.

The cat will experience a lot of soreness after surgery and needs to be kept quiet during healing. If the incision was in a place the cat can reach, he will likely have to wear a collar that prevents licking or biting at the surgical incision site. Set up a crate or spot in a quiet area of the house where the cat can convalesce without disturbance. Make sure it's large enough to include the cat's litter box and food dishes in addition to a comfortable, roomy bed.

There will likely be quite a bit of pain, as well. Your vet can prescribe pain meds for this. Follow the instructions carefully to avoid overdosing the cat. Keep the incision site clean and dry. 

Quality food and plentiful water are essential during the recovery phase, but be aware that your cat is not as active at this time, so don't overfeed him. Cats who don't feel well usually do not want to eat, so you may need to learn to use a syringe or feeding tube to make sure your cat is getting proper nutrition so he can heal. 

This is especially true for cats who have had a large section of their upper jaw removed. These cats will need softened or liquefied food and will likely need some help eating at first.

There will be many follow-up visits to the vet, usually every few months, to check for healing and recurrence of the cancer and to make sure it was all addressed during surgery or treatment.

A Cat's Prognosis with Chondrosarcoma

Although rare, these cancers are particularly aggressive. Depending on the location of the tumor, the cat's quality of life may be something to which he can adapt, or it may be very low. If the latter is the case, many owners opt for euthanasia rather than putting the cat through the surgery to remove the tumor. A cat can live several years without a leg, but if the tumor is in an inoperable location or if so much of the jaw must be removed that the cat will not be able to eat, euthanasia may be kinder.

Tumors in the nasal and sinus passages tend to be quite aggressive, so a cat's prognosis with them is guarded.

Most cats with this type of cancer in the bones have a poor prognosis, although cats do better than dogs. Survival rates are higher if the tumor is on a limb rather than on the body (the axial skeleton). Limb tumors tend to spread less than axial ones. One case study documented a cat where the tumor was on the scapula (shoulder blade) and the entire scapula was removed. The cat went on to live a normal life, able to run, jump, and play just as before. Tumors affecting the joints cannot be easily removed with surgery, and survival rates are much lower.

Chondrosarcomas are less aggressive than osteosarcomas, so if your cat has to have bone cancer, this is the preferred kind. If you catch it early, before it has spread, and the surgeon is able to remove all of the tumor, your cat may have many more years with you.

Tuesday, May 21, 2013

Cancer in Cats: Mast Cell Tumors

Cancer in Cats: Mast Cell Tumors

The series on cancer in cats for Pet Cancer Awareness Month continues with an in-depth look at mast cell tumors, also known as mastocytomas or MCTs. These fairly common connective tissue tumors represent about 20% of all feline skin cancers (the second most common skin cancer in cats) and 33% of all feline gastrointestinal tumors. However, they are less common in cats than they are in dogs.

What Are Mast Cell Tumors?

In a cat's normal immune system, mast cells are created by the bone marrow and migrate to the body's peripheral tissues to mature. They are found throughout the body in connective tissue as a part of the immune system, but mainly in the skin, the linings of the respiratory and digestive tracts, and the nose and mouth. Mast cells don't circulate in the blood, like the lymphocytes we discussed in a previous post, but remain in these connective tissues. They are also specifically designed to combat parasites.

Mast cells help regulate the nerves in the skin, blood circulation, the body's fibrous tissue, and immune cells. They are closely related to allergy, as they release histamine granules to combat allergens introduced to the body, which the mast cells react to just like they would to parasites. This helps the body fight off the irritating allergen. But histamine is not the only substance they release in response to parasites they encounter in the body.

When tissue is injured, the mast cells respond and assist with keeping blood flowing to cleanse a wound by activating the blood platelets to function properly. They release heparin, an anti-clotting agent that may also have additional unknown functions. They also release other granules that tell the phagocytes to "eat" foreign cells or dying cells. These substances they release cause inflammation (swelling) at the site of the wound. Within hair follicles, mast cells regulate their activity.

An MCT is an abnormal mass of unstable mast cells that form a small nodule. As the cells destabilize, they begin releasing large amounts of granules into the cat's system.

When released in normal quantities, these substances help the body's immune system to function properly. But when too much of them is released, they become irritating to the body's tissues and have unintended effects. They can cause clotting problems with the blood (90% of cats with a tumor on the spleen experience this) and ruin the collagen that supports the skin structure around the tumor.

If untreated, the tumor may clear on its own, or it may start spreading. It first moves to the cat's lymph nodes, and from there to the liver, spleen, and bone marrow. About half the time these tumors in cats will involve the spleen or intestines. They are the third most common type of intestinal tumor in cats.

What causes the cells to become abnormal and gather into a tumor is unknown. It's also unknown what causes some tumors to be benign and others malignant. Because mast cells vary with each individual's genetic makeup, it has been difficult to identify any particular factor or factors that cause the cells to become cancerous or to spread.

What Symptoms Would My Cat Have?

Because of the many different functions of mast cells, these tumors may cause a variety of symptoms in your cat that can be somewhat difficult to identify at home. Ulcers in the digestive tract and itchy lesions on the skin are two of the most common. The tumor may appear as a little hard, white, flattened area or nodule. Sometimes they are pink. Since these tumors have a lot of histamines in them, they tend to itch and get inflamed. Some describe them as looking like the eraser on a wooden pencil.

The growth may be on top of the skin or a lump just underneath it. These tumors under the skin are unique to cats and sometimes go away spontaneously; they're the ones to which Siamese and Sphynx cats are more susceptible. The tumor may appear to get bigger, and then smaller. It may be hairless...or not. At first, it may resemble a flea or mosquito bite, a wart, or some type of allergic reaction.

You might notice such a growth that appears to be fairly stable, but then after several months it starts to grow rapidly. It may redden and have an accumulation of fluid in it. There may be multiple MCTs, or only the one.

Typical locations for these growths are on the cat's head and neck or the trunk of the body. Common places to look for them are the base of the ear, cheek area, near the eyes, or the top of the head. Less commonly, they are found on the cat's legs or paws. Internally, they could be anywhere in the digestive tract, respiratory system, or spleen.

If you manipulate the little growth, it may get red and swollen. This is from the histamine being released by the mast cells in the tumor. Try not to do this much before taking the cat to the vet, as it can increase the chance of it spreading.

The lymph nodes may swell near the tumor as the cat's immune system tries to fight it. This can also be a symptom that the cancer has spread to the lymph nodes. Once it becomes widespread in the cat's system, the liver and spleen will become enlarged.

If the tumor is internal or if it has spread to the internal organs, your cat may have a loss of appetite and experience vomiting and/or diarrhea. There may be some uncontrollable bleeding, especially if the tumor is in the intestines (90% of tumors located here cause blood clotting difficulties). If the tumor is in the lungs, it may be difficult for the cat to breathe. About 1/3 of cats will also become anemic and lose weight as body fat and muscle are depleted (also known as "wasting" or "cachexia"). Anemia is more common in cats with a tumor on the spleen.

Cats average around 10 years old when these tumors appear, but they have been seen in cats under a year old, and in cats as old as 18 years. The more benign form of the tumors are more likely on cats averaging around 2.5 years. Intestinal MCTs are more common in older cats.

Siamese cats seem more susceptible to mast cell tumors than other breeds of cats. Young ones are especially prone to getting the ones under the skin known as "histiocytic" MCTs. About 50%-90% of the time, these are benign and will go away on their own.

Young Sphynx cats may also develop small lumps of mast cells of this type that resolve on their own. The older the cat when the tumors appear, the less likely they are to disappear spontaneously.

How Would I Know For Sure If My Cat Has An MCT?

Your veterinarian will ask you about the symptoms you have noticed, so make careful notes on these at home when you find them. A physical exam will include checking the lymph nodes for swelling.

Some cells will be needle-biopsied to check for mast cells in the cat's blood (fine-needle aspiration). A surgical biopsy will help identify the grade and stage of the disease. Special precautions will need to be taken for cats that have

Depending on the preliminary examination, cell samples may also be taken from a nearby lymph node, the bone marrow, or from the cat's kidneys or spleen. These will be sent to a specialized lab for analysis.

The vet may also take an X-ray and ultrasound imaging and/or a CT scan. This will help locate the exact placement of the tumor and see how far it may have invaded the adjacent tissues.

How Are Mast Cell Tumors Treated?

It's important to seek treatment by a veterinarian for a mast cell tumor quickly, as they can be malignant and spread to other sites in your cat's body. You will likely be referred to a veterinary oncologist, who specializes in treating cancer in pets. Which treatment protocol is used will depend on the nature of the tumor and the stage of cancer when diagnosed.

Since these tumors typically contain a lot of histamine, an antihistamine may be prescribed for your cat. This will help with the itchiness of the tumor. It also benefits the organs so they are not damaged by so much histamine being released into the system as the tumor is manipulated and removed. This type of drug is often used prior to surgery for this purpose. A great amount of histamine released into the system can cause ulcers in the digestive tract or small blood clots.

Surgery to remove the tumor itself is typically the optimal, and often the only, course of treatment. It's recommended that the surgeon remove a "wide margin" of surrounding tissue to make sure and get all of the cancerous cells. If the tumor has affected the spleen, the spleen will be removed. The nearby lymph nodes may also be removed if the mast cells have begun invading them, but not always.

Radiation is not normally used on this type of cancer unless the tumor cannot be completely removed by surgery. This could be due to its location or the inability to remove adjacent tissue. Chemotherapy is often used in conjunction with spleen removal for tumors that have affected the spleen when mast cells are detected in the cat's blood. H2 or calcium channel blocker drugs may be given to protect the stomach from histamine.

After surgery, your cat will need to have blood work done at your vet from time to time, especially when chemo is used for treatment. You'll need to protect your cat from infectious diseases during treatment and recovery, as the immune system will be compromised.

A healthy diet with good nutrients and supplements to boost immunity is also recommended. This will strengthen your cat's body and speed recovery. Eliminating carbohydrates, which encourage inflammation, is recommended. Your vet can advise you on the types of supplements that would most benefit your cat. Omega-3 fatty acids are one type of supplement that seems to help.

Some vets also recommend that cats who have had a mast cell tumor never again be vaccinated. However, depending on your local laws regarding rabies vaccinations, this may not be possible.

What is My Cat's Prognosis If Diagnosed With a Mast Cell Tumor?

This depends on the type of tumor, as well as its location. Obviously, catching it sooner is always better. You can detect some of these tumors within days of their appearance. Many of them are benign.

Once examined under a microscope, mast cell tumors get a "grade" from 1 to 3 that is influenced by several factors, including the tumor's location, how inflamed it is, and its appearance compared to a normal (non-cancerous) cell, or "differentiation". However, this system is more useful for analyzing tumors in dogs than in cats. And because there are no clearly defined standards, grading varies greatly from one pathologist to the next.

Within cats, mast cell tumors on the skin (cutaneous MCTs) are generally classified as "compact" or "diffuse". The former type is generally more benign, while the latter is more likely to spread. Internally (visceral MCTs), there are three forms of tumors: "smooth", "diffuse" and "nodular". 18% of cats who have a cutaneous MCT also have one on the spleen.

The cancer is also given a "stage," depending on its progress at the time it is diagnosed and its likelihood of spreading.

A Stage 1 tumor will likely be a single tumor that has not spread any further. This is the typical type of mast cell tumor that will be found in cats.

Stage 2 would be a single tumor that has spread into nearby lymph nodes.

Stage 3 involves multiple tumors, or by one single large tumor that has invaded adjacent tissue under the skin. There may or may not be involvement of the lymph nodes.

Stage 4 involves a tumor that has spread to the organs, or where the mast cells are present in the cat's blood.

If the tumor can be completely removed, your cat has a good chance of surviving. Some tumors will return (about 23% of the time). Some may simply disappear on their own, even if there are some neoplastic (cancerous) cells in the nearby lymph nodes.

If the tumor is on your cat's paw, muzzle, or in the digestive tract, the prognosis is more guarded. But even cats with internal tumors can enjoy long-term survival if treatment is sought before it has spread.

Once the cancer has spread widely, the prognosis is not good. This is more common with tumors in the spleen or intestines, as they are more difficult to identify early. Most of the cats with these types of tumors either die or are euthanized soon after diagnosis.

Cats with poorer outcomes are those that have lost a lot of weight or who are unable to eat. If your cat is eating well at the time of treatment, the prognosis is much more optimistic. Male cats also have a slightly less likely chance of recovering well from mast cell tumors in the spleen.

The key is to get your cat to the vet as soon as you suspect a mast cell tumor. Keep the cat from scratching, rubbing, or licking the area, as this will only irritate the tumor and increase the amount of histamine being released by the mast cells. A specially designed collar to prevent the cat from grooming will be helpful.

Keep any ulcerated growths clean. This also holds true for the surgical incision area once the tumor is removed. If you notice severe swelling or bleeding at the incision site, call your veterinarian.

If the tumor can be removed and the cancer has not spread, once it shows no sign of returning after about six months, the prognosis is good. Check your cat carefully for tumors that may appear elsewhere. Malignant tumors will usually reappear in another site within two or three months after removal of the initial one.

Watch for more upcoming posts on other types of cancer in cats throughout May for Pet Cancer Awareness Month. While it's a lot more fun to look at cute and funny pictures of cats, it's also important that we pay attention to the health of our feline companions.

Sources: "Types of Cancer in Cats", PetWave; "Mast Cell Tumor (Mastocytoma) in Cats", Pet M.D.; "Mast Cell Tumors in Cats", Pet Cancer Center"Mast Cell Tumors in Cats", VCA Animal Hospitals; "Intestinal Mast Cell Tumors in Cats", "Mast Cell Tumor", and "Splenic Mast Cell Tumor", Veterinary Society of Surgical Oncology; "This is One Lump You Can't Ignore", Healthy Pets with Dr. Karen Becker; "Mast Cell Tumors", Marvista Vet"Mastocytoma", Wikipedia.

Saturday, May 18, 2013

Cancer in Cats: Feline Leukemia

Cancer in Cats: Feline Leukemia

My series for Pet Cancer Awareness Month continues with a Q&A on leukemia in cats. Strictly speaking, leukemia is a cancer affecting the white blood cells. But the virus that causes it, also known as FeLV, is a retrovirus that can also cause several other fatal diseases in cats. Because the terms are used so interchangeably, this post will discuss them both.

Retroviruses produce an enzyme that allows these viruses to insert copies of their genetic material into the cells they infect. Rather than killing the body's healthy cells, they transform them into cells like themselves. This is how these viruses multiply in an infected cat's body. The feline immunodeficiency virus (FIV) is another type of retrovirus, although its cells are more oval in shape, whereas FeLV cells are circular. The two retroviruses have several other distinct differences, chiefly that a cat infected with FIV may never develop any symptoms, whereas an FeLV+ cat will develop some type of disease related to the virus.

Is There a Difference Between Leukemia and FeLV?

Yes. Leukemia is a type of cancer. It causes the number of white blood cells, or leukocytes, in the blood to be far higher or lower than normal. It can cause failure of the cat's immune system or the development of tumors. About a third of all the cats who die from tumors die from a tumor caused by leukemia, and about 1% to 2% of all cats have leukemia.

In a healthy cat's body, the leukocytes help the immune system fight off infections. These white blood cells either consume pathogens trying to invade the body, or they produce antibodies that will attack them. Leukocytes are produced in the body's bone marrow, spleen, thymus, lymph nodes, and tonsils. There are five different types of them, each with a specialized function.

Leukemia tends to mainly alter the lymphocytes (the cells produced in the lymph nodes that mark invading cells for destruction) and neutrophils (the immune system's first responders to inflammation). The virus also damages the cells in the bone marrow that produce blood platelets (megakaryocytes) and the red blood cells that carry oxygen to the body's cells (erythrocytes).

FeLV (Feline Leukemia Virus) is a retrovirus that can cause other diseases in addition to leukemia. Approximately 2%-3% of all cats in the US have it. Because retroviruses can integrate themselves into a cat's DNA, they affect many things beyond the blood. There are actually four subgroups of FeLV. Which disease it causes depends on the particular subgroup of the virus.

  1. Subgroup A is the original form of the virus that exists in all cats infected with it. This type is easily passed from one cat to another. It is less likely to cause the symptoms of actual cancer than the other three types. But along with the FeLV-A virus, in every infected cat, one of the other subgroups of the virus also exists.
  2. Subgroup B causes tumors, or lymphosarcoma, also known as lymphoma, which we discussed in an earlier post this month
  3. Subgroup C is the one that causes leukemia: damage to and depletion of red blood cells (severe anemia) and a proliferation of white blood cells.
  4. Subgroup T attacks the lymphocytes, causing a variety of seemingly unrelated, non-cancerous conditions that include arthritis, spontaneous abortion in pregnant queens, and suppression of the immune system that leaves the cat vulnerable to many other diseases.
When testing for FeLV in your cat, all subgroups of the virus can be detected, but testing does not reveal which of the four are present in your cat.

How Can My Cat Get FeLV?

Cats catch the FeLV virus by being exposed to the saliva, tears, and nasal secretions of infected cats. Other bodily fluids (e.g., urine, feces, milk) also contain the virus. If your cat has close contact with another cat who has the virus, your healthy cat can become infected with it. Mutual grooming is one means. Fighting with other cats is a leading cause of transmission, as a bite wound puts highly infectious saliva directly into the bloodstream. Mating is another, since male cats may bite females during this act. Sharing litter boxes or food and water dishes is less of a concern, but can still spread the virus.

Kittens can also get the virus from their mother while still in the womb, through the placenta. After being born, they're still being exposed to the virus during nursing, through their mother's milk. Some kittens exposed to it this way will fight off the virus and never develop actual leukemia. Others will carry the virus, but could appear perfectly healthy for many years before the disease progresses to one of the other three types. Aside from kittens, who are highly susceptible, elderly cats are more susceptible to infection with FeLV.

Among healthy cats, some can apparently fight off FeLV naturally when exposed to it. These cats may run a slight fever, have swollen lymph nodes, lose their appetite, and become lethargic as their bodies fight the virus, usually for no more than 10 days. This happens about 40% of the time in adult cats and around 70% in kittens. These cats may shed the virus for several months in their bodily fluids, but the infection is usually completely gone within six months. They will live a normal, healthy life and never suffer any symptoms.

About 30% of cats exposed to FeLV will develop an active infection of the virus that will eventually be fatal. These cats typically develop actual leukemia, with all its associated symptoms. White blood cells are greatly increased, but they are defective due to having been altered by the virus. This has the effect of suppressing the cat's immune system, making him more susceptible to all types of diseases caused by bacteria, viruses, fungi, and protozoa.

The remaining 30% of cats will carry the virus, but test negative for it. They may develop lymphoma that is actually caused by the undetected presence of FeLV in their bodies. Typically, the tumors will be in the cat's chest, spleen, kidneys, or spinal area. These cats will not respond as well to treatment of the lymphoma as would a cat that is not infected with FeLV. This is especially true if the tumor is of the acute lymphoblastic leukemia (ALL) type, which involves immature white blood cells that develop quickly.

FeLV is not contagious to humans or other types of pets, only to other cats. The main danger to a human who has an FeLV+ cat is to the pocketbook! (And, of course, to the emotions.)

How Can I Tell For Sure If My Cat Has the FeLV Virus?

Your veterinarian will need to take a blood sample from your cat and test it. This is known as the ELISA (enzyme-linked immunosorbent assay) test and can be done right in your vet's office. The virus protein will show up in your cat's blood. It can be detected within a few days after a cat becomes infected with the virus. Vets typically do this test as part of a cat's initial blood work on a patient's first visit.

There is a second test, known as IFA (indirect immunofluorescent antibody assay), that requires processing by a specialized laboratory. It checks for signs of the virus protein in the white blood cells. If your cat is showing strong symptoms of FeLV infection but the ELISA test is negative, your vet may want to send a sample off for this test. It's also used to verify a positive ELISA test before a final diagnosis is made.

Cats with a positive IFA result do not have a good long-term prognosis. They are considered "persistently viremic," meaning that the disease will progressively become worse until it kills them. Most cats are already in this stage when the disease is discovered.

A needle biopsy may be done to extract some cells from any masses, lymph nodes, or body cavity fluids. The final diagnosis of FeLV infection will be made after microscopic examination of these tissue biopsies to look for cancerous cells.

What Are the Symptoms of Leukemia?

In the early stages, your cat likely would show no symptoms and may appear perfectly healthy. Within two to four weeks of infection, however, the virus is already at work, getting established and replicating itself within your cat's body. The cat may have a mild fever and seem like he doesn't feel well. As discussed above, if your cat is successful in fighting off the virus, these may be the only symptoms ever exhibited, and your cat may go on to live a normal, healthy life.

The lymph nodes may be slightly swollen, especially in the neck area, since the virus first establishes itself there. As the virus injects itself into more and more of the cat's blood cells, you may notice that your cat will alternate between being well and having some type of illness. There's typically a loss of appetite that will lead to weight loss. There is usually some vomiting and diarrhea, as well. The diarrhea may be bloody.

Because the cat isn't getting proper nutrition, the coat will begin to appear dull and in poor condition. You may notice that your cat's gums and the inside of his mouth appear pale from anemia. Your vet may discover a persistent fever as your cat's immune system becomes more active with the overabundance of white blood cells.

Inside your cat's body, the disease is causing all the blood vessels to swell and the joints to become arthritic. The intestines are swelling. The blood vessels in the kidneys are swelling and there is increased albumin being released into the cat's blood. White blood cells are abundant, but they have been damaged so they can't function properly. Red blood cells may be abnormally large. In about 10% of affected cats, the red blood cells will actually rupture and release the hemoglobin in them that carries oxygen to the cells. There may be painful, abnormal bony growths developing in the connective tissues.

Over time, the cat will develop oral problems. You'll notice fishy breath. The gums may become swollen due to gingivitis and some teeth develop a condition known as stomatitis, which makes them painful enough to require surgical extraction by your vet. The cat may also have a tendency to bleed more easily as the number of clotting cells in the blood decline.

If your cat is pregnant, she may spontaneously abort the litter. 60% of cats who abort litters turn out to be FeLV+. If she carries the kittens to term and they have not died in the womb, they will also be infected with the virus, having contracted it from their mother's placenta. (But, remember, some may fight it off and go on to be healthy cats.) If the queen is carrying the virus but has not yet developed symptoms, she can still pass it on to the kittens through her milk. If your breeding female (queen) is infertile, it could be due to FeLV. 68%-73% of the time, this is the case with infertile queens.

As your cat's immune system deteriorates, he will get infections on his skin or ears, and also in the urinary tract (UTIs) and upper respiratory system (URIs). The cat may avoid the litter box with each UTI because it's painful to urinate. Each infection must be treated as it occurs, with bacterial infections usually more responsive to treatment with antibiotics. Fungal and viral infections are tougher to address. There will likely be recurring diarrhea at this point, which can be worsened due to antibiotic treatment killing off the beneficial bacteria in the cat's digestive system.

The cat will begin to suffer neurological damage that can cause behavioral changes and seizures. The vision will also be affected. The cat's pupils may appear uneven in size. The cat may become incontinent. The back legs may be paralyzed. Late in the disease progress, the cat will undergo severe wasting before death.

In some very rare cases, a cat will test positive for FeLV and the virus will be multiplying in the cat's body, but it is trapped in the cat's epithelial cells because the cat is producing antibodies against it. In these cats, the ELISA test will be positive, but the IFA test negative. These cats could still eventually develop either leukemia or lymphoma from the virus.

Is There a Treatment for Leukemia in Cats?

FeLV does have a U.S.-approved drug for fighting it, known as LTCI from a company called T-Cyte. It is also used to treat FIV, and has even shown promise against FIP (feline infectious peritonitis).
This drug will not eradicate the virus from a cat's body, merely treat its effects by restoring immune function. It does this by boosting lymphocyte production and function, amplifying the production of interleukin-2 that regulates white blood cell activity, and increasing red blood cell counts to combat anemia. It does require multiple injection sessions spread out over several months. The company's website has a page you can print to take to your veterinarian in case (s)he has not heard of this drug.

In Europe, a type of Interferon marketed as Virbagen Omega is being used to treat FeLV. This is a veterinary form of Interferon that is also used to treat parvovirus in dogs, and both FeLV and FIV in cats. It may cause more diarrhea in some cats, but has reduced mortality by 20%-30%.

Once the actual leukemia develops, the only real treatment option is chemotherapy. It is effective in some cases, while others do not respond to it. Most cats who develop leukemia survive less than a year. But even if your cat is one of the lucky ones to survive, he will always continue to carry the FeLV virus in his blood.

Infections must be treated individually as they occur. Certain types of antibiotics are better for treating infections in FeLV+ cats because they also combat the Haemobartonella bacteria that can amplify the cat's anemia.

Cats who have tested positive for the FeLV virus should be kept indoors. This is not only to prevent their infecting other cats with the virus, but also for their own protection. Because FeLV weakens the cat's immune system, any type of infection will be more serious in a cat who has it.

Feeding your cat a high quality diet is also recommended. This will improve the cat's overall health and support the compromised immune system. Don't feed the cat any raw foods, as these can carry bacteria to which your cat will be more susceptible. Nutritional supplements, if you can get them in your cat, will also help.

A good oral care program will help with the gingivitis and stomatitis problems. While it won't prevent them, any help you can give your cat in keeping the mouth clean and reducing bacteria there will keep those problems at bay.

Cats who are not eating properly will likely need to be given fluids. You may be able to administer these yourself subcutaneously at home. For anemia, vets may give a blood transfusion. Other treatments will depend on the symptoms your cat exhibits.

Try to minimize stress for your FeLV+ cat. Highly stressful situations for a cat include moving to a new home, introduction of new family members or loss of family members, or overcrowding. Cats don't like change in their normal routine. Other cats intruding on their territory, which may be new cats being brought into the home, or even roaming cats they can see through a window in their yard, stress them. Wildlife such as opossums and raccoons roaming through the yard cause a cat's territorial instincts to kick in, as well.

Most FeLV+ cats are not typically treated with steroids, as this can exacerbate the disease's progression. However, in those with chronic lymphocytic lymphoma (CLL) caused by FeLV, steroid treatment can send the leukemia into remission. If your cat develops an FeLV-caused lymphoma, your veterinarian will determine the type of tumor it is and treat it accordingly.

Your FeLV+ cat should see the vet every six months for a weight check, blood and urine tests, even if showing no outward symptoms. The vet will likely give your cat an anti-worm medication during these visits, to eliminate any parasites that could cause further weakness. Closely monitor the cat's health at home, as well, and get the cat to the vet if anything changes. Get any secondary infections treated promptly. Such treatments will likely be extended longer than their normal duration and may be more aggressive, due to the cat's compromised immune system.

By taking these steps, many cats can live a happy and reasonably healthy life for several years after being diagnosed with FeLV. However, 80% of all cats with a positive IFA test live less than three years  after diagnosis, so be prepared for this if your cat is FeLV+. Some people elect to have their cats euthanized when they get the diagnosis, but this may be robbing the cat of some healthy years during which you both could have enjoyed each other. As more severe symptoms develop to the point where the cat's quality of life is bad all the time, euthanasia becomes a more viable option.

Can Leukemia Be Prevented?

In many cases, yes. Keeping your cat indoors unless supervised is the first line of defense.

There is a vaccine available for FeLV that can be administered to kittens. Since it has been given more regularly to cats, the incidence of FeLV has declined dramatically. It is not effective in cats who have already been infected with the virus, so a cat should be tested for FeLV prior to receiving this vaccine. However, for cats who are 100% indoor cats and never exposed to other cats, this vaccine is not typically recommended. It has been associated with some vaccine-associated sarcomas (VASs). And it is not completely effective in preventing infection with FeLV if the cat is constantly exposed to infected cats, so even a vaccinated cat should be kept separate from any FeLV+ cats in your household.

If you discover early that your cat has been infected with FeLV, during the time known as "primary viremia," your cat may respond to treatment and never develop leukemia or lymphoma. But some cats fight off the infection naturally, even without treatment.

Any female cats who test positive for FeLV should be spayed, even if they are purebreds of good pedigree. (It's always recommended that non-pedigreed female cats be spayed regardless of their FeLV status, both to control the feline population and prevent undesirable behaviors associated with hormonal surges.) In fact, depending on the stage of the disease, a female cat with FeLV who is pregnant may suffer a miscarriage. Male cats who test positive should be neutered. This will not only prevent their passing it to females during mating, but also curb their desire to roam and fight, which spreads the virus to other males.

Keep all your healthy cats separate from any FeLV+ cats in your household. If you take in a stray or foster cat whose FeLV status is unknown, keep that cat separate from any healthy cats...and from any infected cats, in case the new cat doesn't have the virus. If one of the cats in your household tests positive for FeLV, immediately have the IFA test done on all your other cats.

If you lose a cat to FeLV, it's safest to throw away all bedding, litter boxes and food dishes before bringing a healthy cat into your home. Although the virus is fragile and doesn't live long outside a cat's body, it's better to be safe than sorry. Replace them all with new ones. If you can't do this, sterilize all the dishes and litter boxes with a bleach-water solution and wash bedding in your washer's sterilizing cycle. Vacuum all your carpets thoroughly and mop all the floors with a disinfecting agent (such as bleach-water). And make sure that any new cat you get who will be at risk for exposure to FeLV is vaccinated. Indoor-only cats who are never exposed to other cats need not be vaccinated against FeLV, although many veterinarians still recommend it in case the cat gets outside accidentally.

Sources: "Leukemia", Morris Animal Foundation; "Feline Leukemia Virus", Cornell University College of Medicine; "Feline Leukemia Virus Diseases", Pet Care Tips from Greenbrier Veterinary Hospital; "Feline Leukemia", 1-800-Pet Meds; "Overview of Feline Leukemia Virus and Related Diseases", The Merck Veterinary Manual.

Monday, May 13, 2013

Cancer in Cats: Fibrosarcoma

Cancer in Cats: Fibrosarcoma

This installment in Old Maid Cat Lady's series on Cancer in Cats for Pet Cancer Awareness Month covers fibrosarcoma. If your cat develops a lump or lesion in an area of the skin, especially if that was the site of a vaccination in past years, it could be cancerous!

What is Feline Fibrosarcoma?

Typically, fibrosarcoma is a cancer affecting your cat's soft tissues, like the skin or connective tissue. It is relatively common. While slow to metastasize to adjacent tissues, it may be quite aggressive locally and can grow rapidly. Some tumors can be more deeply rooted in the underlying tissue.

Three main types of fibrosarcoma have been identified. The first is in older cats, who sometimes will develop an irregularly shaped growth on their body, legs, or ears. Their immune system may be weaker and their metabolic activities may be out of balance, as well. This makes them more susceptible to carcinogens in their environment.

The second is known as vaccine-induced sarcoma, or VAS. More on this below.

The third results from a mutant form of the feline leukemia virus (FeLV). It is the most aggressive of the three and often causes multiple tumors in younger cats.

What Causes Feline Fibrosarcoma?

One cause of this type of cancer in cats is a virus known as the above-mentioned mutation of the FeLV virus, the feline sarcoma virus (FeSV). This type of fibrosarcoma can occur spontaneously.

Another cause of the VAS type of fibrosarcoma is injections. More on this below.

Exposure to radiation can also cause fibrosarcoma, whether through X-rays or from radioactive particles in the air.

What's This About Cancer at an Injection Site?

Some cats have shown a tendency to develop a tumor at the site of a previous injection. Known as vaccine-associated sarcomas (VAS), they could develop anywhere from 2-3 months to 10-11 years after the injection is given. However, they are considered to be extremely rare (1 in 10,000 cats) and the risk of not administering a vaccine is far worse than that of a cat developing a sarcoma. 99% of cats who get vaccinated never develop a VAS.

VASs typically grow in the connective tissue between the skin and muscle. They were discovered in 1991 at the University of Pennsylvania School of Medicine. First associated with rabies vaccines, they were soon found in cats who had been vaccinated against feline leukemia virus, panleukopenia, and rhinotracheitis. Some studies are focusing on the inflammation caused by vaccinations, to which some cats are more susceptible regardless of the type of vaccine being given.

The role vaccinations play in causing these sarcomas is not really proven. There seems to be more of an incidence when killed-virus vaccines are used. This is hypothesized to be due to the addition of a "booster" known as an adjuvant that is added to killed-virus vaccines to help stimulate the immune system and make the vaccine more effective. Vaccines containing aluminum as an adjuvant have been shown to produce more inflammation (swelling) at the injection site after they have been given, and this factor has been shown to increase the risk of the cat developing a VAS.

Most VASs occur in the shoulder or the rear haunch area, which are common locations for these injections to be given. Fibrosarcomas likely resulting from vaccines have a tendency to be more aggressive and more malignant than those resulting from other causes.

Studies continue on the relationship between vaccines and fibrosarcomas in cats. Some cats have also developed five other types of tumors at vaccine injection sites. As many as six different types of tumors have been observed affecting the muscle, bone, cartilage, or fat at injection sites. Different methods of administering vaccines are being explored to completely eliminate this risk.

Our feline companions are considered to be more at risk for VASs than are other types of pets because cats have a higher sensitivity to chemicals that have their oxidation status changed (oxidative injuries). These substances include onions and acetaminophen, both of which are harmful to cats. Their susceptibility to this condition likely increases cats' risk of developing a VAS in vaccines containing aluminum.

What Symptoms May Indicate Fibrosarcoma?

You would likely first notice a lump or lesion that appears to be just underneath your cat's skin. It could be on the head, body, or legs...or even in the mouth. Oral sarcomas are the second most common type of oral cancers in cats.

The lesion may just appear as an area of swelling, and could be fleshy or firm. It may not be painful for your cat. The lump is often irregular in shape. Sometimes it looks ulcerated, in which case it has probably been there longer. If such a lump does not go away after about 3 months, if it is more than  3/4" across, or has increased in size, a biopsy is warranted.

Fibrosarcomas can also develop inside the cat's body, typically in the connective tissue in the ribs, pelvis, spine, or head areas. This tissue connects the body's bones to the muscles. In these locations, likely because it takes longer to discover, the cancer has a lower survival rate than those found near the skin.

If left untreated or undiscovered until the cancer has advanced, the cat may have difficulty chewing or eating, lose his appetite, get dehydrated, appear to be in pain when walking, become lethargic, or have unexplained bleeding from the mouth. Some may have a bad odor in the mouth, if this is the location of the tumor. By the time these symptoms develop, the cancer is likely quite advanced.

How Can I Be Sure It's Fibrosarcoma?

If you discover such a lesion on your cat, get thee (and thy cat) to the veterinarian!

Your veterinarian will do a thorough physical examination, blood testing, biochemical profile, urinalysis, a tumor biopsy, and X-ray of the tumor site to determine its size, and possibly a chest X-ray to see if the cancer has metastasized. The biopsy will tell the doctor whether this is a fibrosarcoma or an osteosarcoma, which has a different course of treatment.

What is the Treatment for Fibrosarcoma?

The first thing is to surgically remove the tumor. This will likely also include a margin of adjacent tissue, since these tumors are so locally aggressive. They have tiny, microscopic cells that extend like little fingers or tendrils into the tissue surrounding them, so it's very difficult to remove all of it. If it's on a limb, the tumor will likely cause the cat to lose that limb to surgery. Most recover and function just fine with three legs, and many cats have even lived a happy life and learned to adapt with only two! Obviously, younger cats are better surgical candidates, as older cats can have issues with anesthesia. Yes, this is some serious, major surgery. If possible, have it done by a surgeon who specializes in it, rather than at your local vet's office.

Some states are now experimenting with a vaccine against fibrosarcoma that can be given at the time of surgery to decrease chances of a recurrence. Because it is only experimental, the USDA prevents its being given to cats who have not already had a fibrosarcoma. As of 2012, this vaccine was only available in Arizona, Florida, Georgia, New York, North Carolina, and Tennessee.

Radiation therapy may also be performed both before and after surgery to minimize chances of recurrence and reduce the pain for your cat. It kills any residual cancer cells remaining after surgery, as it is difficult for a surgeon to remove all of them. The best outcomes are when radiation is given before surgery and when the tumor can be cleanly removed during surgery. When administered after surgery, radiation can cause the surgical wound to heal more slowly. The cat's hair near the incision may also grow back in a different color, usually gray or white.

Chemotherapy for fibrosarcoma in cats is actually also very effective, especially in cases where the cancer has metastasized (spread). The chemo is typically administered to the cat four or five times, every few weeks for about 90 minutes per treatment. Sometimes it can be injected at the time of surgery to kill any cells that were missed in the surrounding tissue. Chemo is very physically tiring for the cat and rough on the body, so most vets consider it the option of last resort. Your cat will probably also be prescribed something to relieve pain.

Treatment is generally very effective at fighting this type of cancer in cats, with most patients still in remission two to three years later. However, fibrosarcoma also often returns, so once a cat has been diagnosed with it, more frequent visits to the vet are recommended. Subsequent vaccination sites should be closely monitored to make sure another sarcoma does not develop there.

A diagnosis of fibrosarcoma is not an automatic death sentence for your cat; many cats live long and happy lives after the cancer is removed. But as with all cancers, it must be caught early and treated, or it could become life threatening. The chance of a fibrosarcoma spreading to the major organs is only 3%-5% if caught early. But if it goes untreated, that risk rises to 24%. Younger cats also stand a better chance of recovery than older ones.

Is There Any Way To Prevent Fibrosarcoma?

When it comes to the VAS type of fibrosarcoma, yes! Cats only really need one annual vaccination, and that's for rabies. The others are not necessary. Less injections mean less injection sites, so less risk for the inflammation that can lead to a VAS. Have your veterinarian run a blood titer to determine your cat's immunity level before automatically getting vaccinations for everything every year. Then you can only have your vet give vaccines for those where kitty's immunity has fallen low.

Next, when getting your cat's vaccinations, request a recombinant rabies vaccine rather than an inactivated one. And make sure that any vaccines your vet is using are non-adjuvanted. These typically must be given more frequently, but are less likely to cause the inflammation around the injection site that is associated with VASs.

Make sure that the needle your vet is using on your cat is no larger than 25 gauge. Dogs may be able to handle larger needles, but the smaller ones will cause less irritation for a cat, as they will carry less debris and hair with them under the skin. You may also request a vaccine that is administered intra-nasally. There are newer vaccines on the market now that require no injection at all. These present the least risk for VASs and would be especially important to use on cats that have previously been treated for a VAS. If your cat needs another type of medication that can be given orally rather than by injection, opt for that. No, it's not fun to give a cat a pill, but it's far better than putting your cat through expensive and dangerous surgery, radiation, and chemo!

Massaging the area where the vaccine was given may also help by spreading out the material injected into the body. This must be done just after the shot is given. And make sure your vet keeps detailed records on the brands of vaccines used and the sites at which they were injected into your cat. This can be very helpful if you detect a lump that requires further investigation.