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:

• Lymphoma on May 3
• Oral Squamous Cell Carcinoma on May 8
• Fibrosarcoma on May 13
• Feline Leukemia on May 18
• Mast Cell Tumors on May 21
• Chondrosarcoma on May 24
• Hemangiosarcoma on May 27
• Melanoma on May 30

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.

Fibropapilloma 

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.

Osteosarcoma 

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.

Ameloblastomas 

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 OldMaidCatLady.com! And hopefully this series has done some good for Pet Cancer Awareness Month. Thanks for sticking with me through it!

Sources: "Types of Cancer in Cats", PetWave; "Basal Cell Tumors in Cats" by Dr. Bari Spielman, Pet Place; "The Five Most Common Feline Tumors", VetMed; "A cerebral granular tumor in a cat", PubMed.gov; Skin Diseases of the Dog and Cat: Clinical and Histopathologic Diagnosis, Gross, Ihrke, Walter, Affolter; Consultations in Feline Internal Medicine, Volume 6, John R. August; "Feline Liver Cancer Diagnosis", Vet Info; "Liver Tumors: Diagnosis and Treatment", Pastor & Bachs, IVIS.

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.

Sources: "Types of Cancer in Cats", PetWave; "Feline Vaccination Associated Cancer: What You Can Do To Prevent It", Ron Hines, DVM, Ph.D.; "Vaccine Associated Fibrosarcoma", Veterinary Partner; "Feline Fibrosarcoma Explained", Vet Info;  "Feline Fibrosarcoma", South Carolina Veterinary Specialists; "Feline Fibrosarcoma", Michigan Veterinary Specialists; "Feline Fibrosarcoma - Causes, Symptoms, Diagnosis and Treatment", Cat World; "Feline Fibrosarcoma", Cats With Cancer; "Vaccine-associated sarcoma", Wikipedia; "What is a Feline Fibrosarcoma?"; Yahoo Voices

Cancer in Cats: Lymphoma

Cancer in Cats: Lymphoma

May is Pet Cancer Awareness Month, and I just learned today of the passing of another cat famous in the Internet. Kenny Pawgers, beloved companion of Maria Soroski of Crazy About Cats, has succumbed to the lymphoma he had lived with for the past couple of years. That's the two of them in the photo above.

As with humans, there are many types of cancer that can attack cats. I've covered some previously, and will address others separately during this month. In Kenny's honor, this one is on Lymphoma.

What is Feline Lymphoma?

Lymphoma is a  malignant type of cancer that originates in a cat's white blood cells, also known as lymphocytes, which make up the body's immune system. It is responsible for approximately 90% of blood cancers and 33% of all tumors in cats. It can also cause a condition known as hypercalcemia.

The lymphatic system is quite complex and extraordinary. In a healthy cat, it has three main functions. First, it helps maintain a balance of fluids between the blood vessels and bodily tissues. Its lymphatic capillaries are interwoven with blood capillaries, tying it closely to the cardiovascular system. Secondly, it plays a major role in immunity through the body's white blood cells. And third, it absorbs fats reaching the small intestine during digestion.

Primary organs of the lymphatic system are the thymus gland and the bone marrow. These are involved only in the immunity function of the lymphatic system. Secondary organs are the lymphatic vessels, lymph nodes, lymphoid tissue and the spleen. These support all three of the lymphatic system's main functions.

There are two types of lymphocytes in the body, known as B-cells and T-cells. Both originate in the bone marrow. T-cells are the ones that identify foreign matter (antigens) in the body, such as bacteria, viruses, toxins, foreign proteins, or particulates (such as allergens), and mark them for destruction. They mature and are "educated" in the thymus gland to recognize the difference between cells that belong in the body and those that don't. But "Thymus U" is a tough school: if they fail their "final exam" on this, the thymus gland destroys them! Once mature, the T-cells move into the secondary organs of the lymphatic system, where they remain. They regulate the immune system from being over- or under-active.

B-cells are the white blood cells that produce the antibodies against antigens, proteins known as macrophages, that attach themselves to these invaders. The B-cells remain in the bone marrow as they mature. Once exposed to a certain type of antigen, the body remembers it so that the B-cells know how to fight it and can produce antibodies more rapidly the next time they encounter it. This is how your body develops immunity to certain diseases upon second exposure to them.

The fluid flowing through the lymphatic system of capillaries is known as lymph. It is made up of fluid and proteins forced out of blood capillaries into the space between the body's cells. This fluid sustains life in the cat by delivering oxygen and nutrients to cells and collecting waste from them. The flow of lymph is regulated by the body's muscle movement. Lymph is carried to the spleen, where it is processed before being conveyed back into the blood. This is how the body balances fluids. The spleen breaks down old red blood cells, stores blood, and filters the blood for antigens. Within a 24-hour period, about half of all lymphocytes in the blood pass through the spleen.

Lymph nodes are located throughout the body. Larger concentrations of them exist in the neck area, near the back of the front legs ("armpits"), and groin. It is here that lymph is filtered before being returned to the blood veins. In the connective lymphoid tissue around the lymph nodes, the B-cells, T-cells, and macrophages are also stored. Two very specialized areas of lymphoid tissue are the tonsils in the throat and Peyer's patches in the small intestine's lining.

Lymphoma can affect both types of lymphocytes, causing them to go into uncontrolled growth and multiplication. They can then collect in a lymph node to form a tumor, which then grows and invades the surrounding tissues and organs, depriving them of nutrients and oxygen. Sometimes these abnormal lymphocytes will travel to other lymph nodes or organs. This is known as metastasizing.

It is believed that lymphoma develops after a cat is exposed to the feline leukemia (FeLV) or feline immunodeficiency (FIV) viruses. This is because the rate of lymphoma among cats exposed to either of those viruses is much higher than for cats who are not. While cats of any age can fall victim to lymphoma, most tend to be 10-12 years old when diagnosed.

Due to the presence of lymphocytes in all parts of the body, this type of cancer can also affect a cat in different locations. For example, cats who are around a lot of smoke from tobacco are at a higher risk for lymphoma that affects the gastrointestinal tract. This may be due to their grooming the particulates of smoke that become trapped in their fur.

What Are the Symptoms of Lymphoma?

Depending on where a cat's lymphoma originates, it can cause varying symptoms. The one symptom common to them all is a loss of appetite.

If the lungs are its target, the cat will breathe with his mouth open, cough, and lose weight rapidly.

If the lymphoma occurs in the cat's gastrointestinal tract (abdomen or liver), kitty will also experience vomiting, diarrhea, bloody or tarry stools, and be lethargic. This is the most common type of lymphoma seen today.

If the lymph nodes are its target, the cat will have swollen lymph nodes in the location of attack, which could be the jaw, under the arms, or in the groin area. Weight loss and depression are additional symptoms.

If the lymphoma occurs in the kidneys, the cat will be vomiting, show increased urination and thirst, and become very weak.

If your cat exhibits any of these symptoms, keep careful notes on which ones so you can give this information to your veterinarian. This will help the vet know where to look for other signs of the cancer. Testing done to confirm a diagnosis of lymphoma will include a physical exam, blood cell count, a blood chemistry panel, urinalysis, X-rays, sampling of lymph node tissue for examination under a microscope, and an ultrasound to check for an enlarged liver or spleen.

Can Lymphoma Be Treated?

While not normally curable, a cat's life can be prolonged a little by treatment. This may include surgery to remove any mass present in the abdomen, chemotherapy, and in some cases radiation therapy. The cat will likely remain on chemotherapy for the remainder of its life, which may be six months to a year or more after diagnosis, with some brief periods in between treatments.

Even better, there are some steps that can be taken to minimize a cat's risk for lymphoma. Indoor cats are less at risk than outdoor cats, so keeping your cat indoors is one step to take. Another is not to smoke around your cats. If you are addicted to smoking, try one of the newer electronic cigarette kits that will allow you to receive the nicotine you crave and enjoy the physical motions of smoking without endangering your cats. The third thing you can do is to get your cat vaccinated against FeLV and FIV and try to keep them from being exposed to other cats who have these diseases.

There are some natural and homeopathic remedies designed to address cancer in cats, but little testing has been conducted to determine their actual effectiveness. This is not to say that they won't work for some cats; every individual's physiology is unique.

Our sympathies to Maria on the loss of Kenny Pawgers. May he fly high, finally free of the suffering he has endured, and remaining close to the person who loved him so. And may she find peace in her time of grief, soon turning her attention to other cats who still need the love she has to give.

Purrs of comfort!

Sources: "Lymphoma in Cats", Pet MD; "Lymphoma in Cats", Veterinary Partner; "Lymphoma", Cornell Feline Health Center; "Structure and Function of the Lymphatic System in Cats", Pet Place; "Lymph Node Inflammation (Lymphadenopathy) in Cats", Pet MD.