Cancer in Cats: Types, Symptoms, Prevention, and Treatment

WebMD veterinary expert answers commonly asked questions about cancer in cats.

By Sandy Eckstein
WebMD Pet Health Feature

Reviewed by D. West Hamryka, DVM

Although cancer isn't as common in cats as it is in dogs, it still affects a number of our feline friends. And because cats have a tendency to mask illnesses, it can be harder to detect. This often leads to later diagnoses and more difficult and costly treatments. So we talked to Dave Ruslander, a veterinary oncologist and past president of the Veterinary Cancer Society, about feline cancers and the latest treatments for cats diagnosed with the disease.

Q: How common is cancer in cats? What are some of the more common cancers found in cats?

A: Cancer in cats is less common than cancer in dogs. It's probably half the rate that we see in dogs. But when we see cancer in cats, it tends to be a more aggressive form.

One of the most common cancers we see in cats is lymphoma, which is associated with the feline leukemia virus (FeLV). Even though there's a vaccine for feline leukemia now, we still see a number of cats that have been exposed to it, and exposure greatly increases a cat's chance of developing feline lymphoma.

We also see oral squamous carcinoma, similar to what people get. We see a tumor called fibrosarcoma, or soft tissue sarcoma, which is a tumor developing in muscle or in the connective tissue of the body. That's the one associated with injections and vaccinations, which some people call injection-site sarcoma.

We see other kinds of tumors as well, but they are much less common -- lung tumors, brain tumors, nasal tumors, liver tumors. We don't see as may mammary tumors these days because so many people have their cats spayed now. So all of those are just a smattering here and there.

Q: What are some of the symptoms of feline cancers?

A: Cats are tricky because they hide disease well. Externally we can see lumps and bumps. Vomiting and diarrhea are common signs of gastrointestinal lymphoma. Difficulty in breathing can be a sign, because some cancers can cause fluid in the lungs.

Sometimes it's just a refusal to eat and weight loss, a rough coat, or just generally what we call a failure to thrive. It's always best, if your cat is acting ill or lethargic for any period of time, to take it to your veterinarian to be checked out.

Q: Is it difficult to diagnose the type of cancer a cat has contracted?

A: With a biopsy the pathologist can usually tell us the type of cancer. But sometimes it's not so clear. And sometimes people are reluctant to go forward without a firm prognosis. Often we can't go forward until we know what the actual subtype is. It can take some special testing or some special stains for us to delineate the type of cancer, and sometimes people just aren't willing to do that.

Q: What's causing the high cancer rates in our cats?

A: We really don't know what causes most cancers. There are a few, like the feline leukemia virus, which is the big player in cancer etiology in cats. But I don't know that we have the answer for what causes most cancers in cats.

We do know people are keeping cats longer. Cats are living longer, so of course we see more cancer in cats just because we see more cats. But even in older cats, cancer is more sporadic than it is in dogs.

Q: Can household chemicals or other common items, like bug sprays, cause cancer in cats because they walk through the residues and then lick their feet?

A: There may be environmental causes. There have been some studies looking at secondhand smoke. There have been issues of cats grooming themselves developing oral cancers. But they really don't know if it's because they're taking some toxins from the environment into their body that way or not. There are still a lot of questions about environmental issues.

Q: Are some cat breeds more prone to cancers than others?

A: No, we don't really recognize breeds of cats being at increased risk of cancers like in dogs. However, white varieties of certain cat breeds are more prone to squamous cell carcinoma, usually on their ears and face.)

Q: If my cat has cancer, does that mean she's going to die?

A: No, but many of the cancers we see in cats are more aggressive than those we see in dogs. So early detection and treatment are very important.

Q: What are the treatments for cats with cancer?

A: We have surgery, which is the most common treatment for any kind of lump or bump that needs to be removed. Chemotherapy is used most commonly in the management of lymphomas. But it's also used when we have aggressive tumors that have spread to lymph nodes or other organs.

We use radiation therapy in situations where we can't remove the tumors, for example brain tumors and nasal tumors.

Q: Are we seeing advancements in the treatment of feline cancers?

A: Yes, but because historically people tended to do less for cats than they did for dogs, the advancements have been slower. But we've had advancements with radiation therapy, new and novel chemotherapy approaches, and new surgical approaches as well.

But we haven't seen as many drug advances for cats as we've seen for dogs. A lot more of the research dollars go to dog cancers than go to cat cancers.

Q: How much does it cost to treat a cat with cancer?

A: Probably $500 to $1,000 to do the initial diagnostic testing. Then it costs anywhere from $800 to $2,000 for surgical approaches. Chemotherapy is $2,000 to $3,000, and then radiation can be $5,000 or $6,000. (Note: These are costs for treatment at a specialist. Prices at a general veterinary practice may be much less. Costs may also vary a lot depending on where you live.)

Q: If treated, what's the cure rate for cats with cancer?

A: That's hard to say because there are so many different types of cancers and so many variables. But I would say overall the survival rate for cats, if we're including every type of malignancy, is probably less than 50%. But it all depends on the tumor type, when it is found, and how it is treated.

I would recommend, whenever an animal is diagnosed with cancer, that the owner consult with a veterinary oncologist. Things are changing so fast, not just in terms of treatments but also clinical trials or novel treatments, that there may be treatments available that most veterinarians aren't aware of. You may think there's nothing that can be done, but things are changing all the time.

Q: What can I do to prevent my cat from getting cancer?

A: Spaying your cat will drastically reduce her chance of getting mammary cancer. Preventing the development of feline leukemia, either through vaccinations or making sure when you get a cat that the cat hasn't been exposed to feline leukemia, will decrease the likelihood of developing lymphoma.

But it's so hard to say how to prevent something when you don't know what causes it most of the time. So early evaluation and detection is probably the better approach in terms of improving outcome.