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", Eyevet.info; "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.

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.

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.

Sources: "Chondrosarcoma", Vetstream; "Chondrosarcoma", Vetbook; "Chondrosarcoma (Nasal and Paranasal Sinus) in Cats", PetPlace.com; "Feline chondrosarcoma: a retrospective study of 67 cats (1987-2005)", PubMed.gov; "Tumors Involving Bone in the Domestic Cat: A Review of Fifty-eight Cases", Veterinary Pathology Online; "Bone and Joint Tumors in Cats", VCA Animal Hospitals; "Bone Cancer (Chondrosarcoma) in Cats", Pet MD; "Mouth Cancer (Chondrosarcoma) in Cats", Pet MD; "Nose Cancer (Chondrosarcoma) in Cats", Pet MD; "Throat Cancer (Chondrosarcoma) in Cats", Pet MD; "Total scalpulectomy for the treatment of chondrosarcoma in a cat", Ortho Vet Super Site.

Cancer in Cats: Oral Squamous Cell Carcinoma

Cancer in Cats: Oral Squamous Cell Carcinoma

My series on Cancer in Cats for Pet Cancer Awareness Month continues with a discussion of this painful type of oral cancer. As with all cancers, early identification and treatment will ensure the best prognosis for your kitty.

What is Oral Squamous Cell Carcinoma?

Cats groom themselves all the time, so it's natural that they may ingest carcinogens in doing so. In fact, this is a common type of cancer that accounts for about 10% of feline cancer diagnoses. Oral squamous cell carcinoma (SCC) is the third most common tumor diagnosed in cats. These tumors tend to be fast-growing and invasive, often spreading to adjacent lymph nodes. While there are other causes for oral tumors in cats, squamous cell carcinoma accounts for over 60% of them.

This type of cancer may appear anywhere within a cat's mouth. Most tumors occur underneath the tongue or on the gums, but they can also appear on the roof of the mouth or in the cheeks. They grow rapidly, so acting fast can save your cat's life.

When Should I Suspect My Cat Has Oral SCC?

Quite often, you'll be able to see these tumors. If you brush your cat's teeth, make sure to examine the mouth thoroughly to scan for one. It may show up as a small reddened ulcer that lingers long after it should have been healed. There could also be a small hardened, swollen area along the lower jaw or cheekbone. There may even be more than one. Places to look include the gums and underneath the tongue.

Some cats can develop an enlarged jaw due to the tumor. Kitty's face or jaw may look malformed or a bit asymmetrical. With tumors on the gums, they often metastasize to invade the underlying jaw bone. If your cat has a couple of teeth in the same area that need to be removed, the cause could be an underlying tumor and a biopsy may be indicated. If kitty loses a tooth and the resulting hole in the gum does not heal easily, there may be a tumor.

In the later years of her life, my own little Vixen developed a lesion on her chin that would sometimes swell and bleed. A biopsy revealed it to be benign, but it was a source of worry for me just the same.

Your cat will likely not have much of an appetite, always a sign that something is wrong. You'll notice weight loss, naturally, but the cat may also want to constantly be chewing. Kitty may have difficulty eating. Bad breath and drooling may occur. There may be swelling in the mouth or jaw, and the area may be painful for you to touch. The lymph nodes in the neck may be swollen. If there is a lesion on the gum, teeth near it may be loose. You may also see some bleeding from the mouth.

Feline Oral SCC Risk Factors

Cats have been diagnosed with oral cancer anywhere from ages 3 to 21, so age is not much of a factor. The average age of diagnosis tends to be 12.5 years, so older cats are more at risk. There is no predisposition to it in any particular breed of cat; all are equally susceptible. Several factors may contribute to it, although there is no major cause that has yet been identified.

Living in a house with smokers is one of the most important risk factors for this type of cancer. Even living for a little while with a smoker doubles a cat's likelihood of developing oral SCC. Cats who continually live in a smoke-filled environment are four times as likely to develop it.

Some studies have shown a link between wearing flea collars and developing this type of cancer. This was assumed to be due to the closeness of the collar's pesticides to the cat's mouth area. However, there are so many different types of flea collars that no distinction as to the type that contributed to the cancer could be made.

While exposure to the sun among outdoor cats or white-coated cats can cause tumors on the ears or nose, sun is not typically a contributing factor to oral cancer (unless the cat sleeps in the sun with his mouth hanging open).

Owners who regularly used a flea shampoo on their cats actually reduced the cats' risk of oral squamous carcinoma by 90%. This could be partially due to the shampoo also washing away many of the toxins from the cat's fur that would have been ingested through grooming.

Eating a large amount of canned cat food has also been shown to contribute to a cat's risk factor in developing oral cancer, with canned tuna being the riskiest. This one's troubling to me, as my Golden Boys both love their daily treat of some canned food in a fish flavor! The relationship between canned food and oral cancer may be related to the cats' oral hygiene, as eating dry food keeps the teeth cleaner. No study has been done on cats whose teeth are regularly brushed.

What is the Treatment for Oral SCC?

Not all oral tumors are cancerous; there are several types of feline oral tumors that can be benign. One small study showed that about half of the cats showing symptoms actually had cancer. And there are different types of feline oral cancer, although they are much less common. If the cancer is SCC, it will tend to be extremely fast-growing, invasive and malignant. Only those tumors caught very early are deemed treatable. Once it has spread, the cat's chance of survival is minimal.

Your veterinarian will do a blood count, a serum chemistry profile, urinalysis, and tests for feline leukemia (FeLV) and feline immunodeficiency (FIV) viruses. X-rays, a CT scan, or an ultrasound may also be taken to locate the extent of the tumor's invasion, which can change the course of treatment. The primary tumor will likely be biopsied to determine if it is actually cancerous. This will have to be taken from the cat's mouth, not through the skin. You may be referred to a veterinary oncologist for treatment.

The stage of the cat's tumor will be assessed after biopsy as T1, T2, or T3. The testing will contain additional notes on whether the adjacent bone is invaded, if the cancer has spread to the lymph nodes, and if it has metastasized to other tissues. This gives the vet useful information on whether or not the tumor is treatable. Sometimes it's difficult to determine the type of cancer without additional testing, so a course of treatment is not readily apparent.

If a diagnosis of SCC is confirmed, sadly there is no therapy with great success in treating it. Surgery to remove as much of the tumor as possible, followed by radiation therapy is the most common treatment. That surgery may be quite radical and involve removing a significant portion of the cat's jaw. Cryosurgery (freezing) is now being used on very small tumors. Sometimes a combination of radiation and chemotherapy are used.

Most cats survive only a few months after diagnosis. A rare few have been disease-free a year after surgery. But most owners reported that they were pleased with their cats' quality of life after the surgery and would have made the same decision to do it again had they known the outcome.

The success of surgery depends largely on where in the mouth the tumor occurred. The best location for one to be is on the front part of the lower jaw. Tumors located closer to the rear of the mouth, or those that cross the midsection of the oral cavity typically cannot be completely removed by surgery. In fact, surgery's only role in these cases is to make the cat comfortable for the remainder of its life, which won't be long. The prognosis for tumors like this is so poor that such surgery is referred to as palliative care.

Cats who survive the surgery often have trouble eating due to mouth tissue having been removed, and many of them drool. These complications require their owners to bathe their chests and front paws several times a day. Tumors involving the jaw area are also tricky, and may involve removal of a portion of the cat's jaw. Tumors on the upper jaw are typically inoperable.

Radiation may be used to treat inoperable oral tumors. It is also useful to prevent disfiguring the cat, and is used in combination with surgery for the best outcomes. This type of treatment can also be extended to include adjacent lymph nodes, helping prevent the cancer from spreading. However, the larger the tumor, the less the likelihood of its being eliminated by radiation alone. Radiation is also sometimes used as palliative therapy in cats with advanced SCC, although it rarely prolongs the cat's life for long and can have some unpleasant side effects. A new type of radiation therapy known as stereotactic may hold promise for faster results.

Chemotherapy by itself has not proven effective in fighting oral SCC. When combined with radiation, however, its effectiveness improves slightly. But many of the cats treated with chemo in studies did not live longer than a few additional months. Studies continue on new types of chemotherapy drugs, including histone deacetylase inhibitors (HDACIs) and anti-inflammatories such as LOX and COX inhibitors.

Newer experimental drugs that mirror some being used in human cancer therapy are being tried on cats. Some are showing hope, but it is too early to say for sure.

As this type of cancer is usually extremely painful for the cat, most cats undergoing treatment also require some type of pain therapy. Supplemental nutrition will help their bodies to fight the cancer and may help them feel a little better, even if their prognosis is not good. Some may require a feeding tube, as well. In addition to difficulty eating and drooling, the cats will have trouble grooming and swallowing.

Sadly, 90% of cats diagnosed with oral SCC die within a year of diagnosis. The most that can be done with treatment is to make the cat more comfortable for the remainder of its life (palliative care). Tumors are likely to recur in more than 1/3 of cases, and will eventually make it impossible for the cat to eat or even breathe, at which time euthanasia is the kindest option. The lucky 10% of cats who survive for a year are likely to survive for at least two years. Some may live cancer-free for three years, but most eventually suffer a recurrence of the cancer.

More cancer research funds tend to go to research on dogs rather than cats, as dogs are where the money is; the sentiment among veterinary researchers is that owners tend not to treat diseases in cats as aggressively as they do in dogs and are quicker to choose euthanasia for a cat. Slowly, this is changing...the operative word there being "slowly." Cats' delicate systems are also more sensitive to drugs than dogs, which further complicates both testing and treatment options. Studies funded by the Winn Feline Foundation and The Morris Animal Foundation may yield more hopeful results.

Treatment is pricey; the testing alone could run you up to $1,000 at a veterinary oncologist. Surgery could be another $2,000, with radiation running up to $6,000. Chemo runs $2,000-$3,000. This is one of those times when having a pet insurance policy that covers cancer treatments would have been a very good investment.

As with any type of cancer, your veterinarian can best advise you on your cat's unique situation. The main pointers with oral cancer are to remain vigilant, do frequent inspections of your cat's mouth, don't smoke around your cats, and practice good oral hygiene with both regular home care and annual veterinary checkups/scalings.

Sources: "Feline oral squamous cell carcinoma: an overview", DVM 360; "Oral Squamous Cell Carcinoma (feline)", Marvistavet; "Mouth cancer (Gingiva Squamous Cell Carcinoma) in Cats", Pet MD; "Researchers Focus on Feline Oral Squamous Cell Carcinoma", Purina Pro Club.