Cancer In My Cat – How It Will Affect My Cat And How It Will Affect Me?

  Caring For Your Elderly Cat

  Pain control In Cats



How Likely Is It That My Cat Will Develop Cancer?

That likelihood varies from place to place and breed to breed – but not that much. The Tulsa Registry of Feline Neoplasms was the second-oldest feline cancer registry in the United States. It only registered 470 cases of cancer in the Los Angeles area, which, at the time, was estimated to have had about 100,000 pet cats. But cat owners in those days tended to visit veterinarians less often than dog owners (which is still true). That was in the 1970s, and not much statistical data has been published since. Pet insurance companies here know, but they tend to keep that data under their hats. Agria, which unfortunately does not currently operate in North America, is more forthcoming. In their cat insurance claims in Sweden that ended in mortality, the most common issue in their combined breed chart was urinary tract disease. Trauma, primarily traffic accidents and falls from heights, was the second most common group-combined cause. Cancer was the third most common group-combined cause, but cancer outnumbered other causes in Main Coon and Siamese cats. (see here,   read hereMost of those claims were for pedigreed cats. The price of an Agria cat policy is high because of their generous lifetime coverage. Owners of shelter and rescue cats probably couldn’t afford them. I doubt that it was because purebred cats developed more cancer than ordinary cross-bred cats do. Unfortunately, from their data, it was clear that when cats do develop tumors, most of those tumors are malignant. That is why ten times as many cats die from their tumors than dogs do. (read here) Also, from their statistics, over half of the tumors that occur in cats occur in their skin, or just below it. In a group of Swiss cats, veterinary pathologists examining 18,375 cat tumor submissions decided that 80.3% of them were malignant and life-threatening. As in other study, most often these were malignant skin tumors (27.05%), followed by Lymphosarcoma tumors (21.28%) and sarcomas (19.04%). (read hereAt the RVC in London, only 6.6% of feline skin lumps were not cancerous, and of those that were, 52.7% were considered malignant. The most common ones were basal cell carcinomas, fibrosarcomas, squamous cell carcinomas and mast cell tumors. (read here). Italian veterinary pathologists reported that squamous cell carcinomas, sarcoma, lymphoma and basal cell tumors were the most diagnosed neoplasms in cats in Italy. In 82.9% of those cases, the tumors were malignant.

Decision Bias

Bernard Rollin, the man in this photo, was a friend of mine. He was a professor of philosophy at Colorado State University. He taught me that sometimes the most loving decision you can make for your cat is the one that will hurt you the most. He sent me one of his articles about decision-making for cats in their twilight years. I’ll send it to you if you ask meWhen you discuss your cat’s treatment options with your favorite veterinarian, remember that he/she is obligated to mention all advanced treatment options available at specialized veterinary facilities. But that doesn’t mean that she or he would choose to avail themselves of those sophisticated chemo and surgical services if it was their own cat that faced aggressive cancer. You will have to read between the lines of what your vet tells you when announcing bad news. Mannerisms often tell you more than the words do. Specialty, privately owned veterinary hospitals now exist in most US, European and Asian urban centers. No doubt, they have access to highly competent veterinarians and sophisticated equipment that your local general practice veterinarian doesn’t have. However, the commercial ones are all profit-driven corporations, with salaries to pay and stockholders to please that requires a steady stream of new clients. The college-associated ones are intent on research, writing journal articles and teaching the precepts of oncology to their students. Empathy for cats and cat owners is not a job requirement. The online presence and client brochures of all of them are always upbeat – and just as accurate as the rest of the advertisements you are subjected to online. When you consult a veterinary oncologist, he/she is likely to suggest chemotherapy and/or radiation therapy for your cat. If you consult a veterinary surgical specialist, that person is likely to suggest a surgical cancer option. It’s just human nature to be enthusiastic and upbeat about what you do.


Cancer Due To Your Cat’s Virus Status

House cats are unique among our pets in that they are susceptible to two viruses that cripple their cancer-fighting abilities, the feline leukemia virus and the feline immunodeficiency virus. They do what the HIV virus does to humans. Probably by disabling your cat’s CD4+ cancer fighting “policemen”. FIV-infected cats are said to be five to six times more likely to develop lymphoid tumors than uninfected cats. Some say that if your cat is FeLV+, its chances of eventually developing cancer are 33% greater. And if your cat is positive for both viruses, its changes of developing lymphoma are said to increase by well over 100%. (read here)  Those two viruses, and over exuberant administration of periodic vaccines, account for the majority of tumors in young adult cats. Remember that all these percentages are just veterinarian’s educated guesses.


What Are The Most Common Tumors Of Cats?

The RVC, which has a sterling reputation for accuracy, lists feline tumors in the order of frequency as lymphomas, carcinomas, mast cell tumors, mammary gland tumors, fibrosarcomas, and bone tumors. In one study, 82.9% of the tumors that occur in cats were malignant. (read here)


Lymphoma | Lymphosarcoma 

Most use the terms, lymphoma and lymphosarcoma and lymphosarcoma interchangeably, although a veterinary pathologist might use the second term more frequently – particularly if it is highly malignant (“high grade”). High grade is a term that denotes tumor cells that are rapidly proliferating. Healthy lymphocytes are a critical part of your cat’s defense system against infectious disease. They are also critical in nipping cancerous cells in the bud. But they are not immune to becoming cancerous themselves. For reasons unknown, lymphocytes are more likely to do that in cats than in dogs. Lymphomas often begin as a small clone of malignant lymphocytes in the wall of a cat’s intestinal tract or a lymph node – a clone is the offspring of a single mutant cell. Because lymphocytes are not firmly attached to the cells that surround them, blood and lymph can spread the emerging cancer to almost any place in the pet’s body. Unfortunately, it is very rare for a lymphoma/lymphosarcoma in a cat to be detected before that has already happened. Occasionally, a lymphoma is discovered in a cat’s nose. If it cannot be detected in other parts of the cat’s body, that may well be its primary site. Nasal lymphomas need to be differentiated from chronic sinusitis (perhaps due to feline herpes1 infection) or a nasal carcinoma tumor through biopsies. 

What Signs Of Lymphoma Might I See?

No symptoms of ill health are specific to lymphoma. As lymphoma progresses, declining appetite, weight loss, listlessness and a lack of energy accompany the disease. Once the cancer has moved to secondary organs (metastasized) additional signs pertain to whichever organ(s) are involved. Weight loss, a decreased appetite, diarrhea and/or vomiting come earlier when the primary tumor is in your cat’s digestive tract. That is the most common site for lymphomas to originate. Because of fluid loss and a reluctance to drink, most of those cats arrive dehydrated. When the gastrointestinal tract is the primary site of your cat’s lymphoma, it is easily misdiagnosed at first as inflammatory bowel disease. As I mentioned elsewhere, it can be hard for pathologists to decide from biopsies if the increased number of lymphocytes present are due to inflammation or due to cancer. If secondary tumors involve your cat’s nervous system, heart, lungs or skeleton, additional signs will pertain to those organs no longer being able to perform their duties. A cat’s spleen is another potential secondary site. Your veterinarian might inform you that your cat’s spleen feels enlarged. Unless the FeLV or the FIV viruses I mentioned before are involved, the average age that these tumors begin to develop in cats is 10 – 12 years. The exception is when lymphoma begins in the chest, that often develops at an earlier age, even in FIV/FeLV negative cats. (read here

Do All Lymphomas In Cats Progress At The Same Rate?


The rate at which they grow and the success in bringing them into remission vary greatly.

What Lymphoma Tests Will My Veterinarian Run?

Unfortunately, there are no blood tests, yet, that will detect lymphomas. Early in the disease, your cat’s blood work results are likely to be normal. Your vet might, perhaps, detect that your cat’s intestines feel a bit thickened on palpation, and its age, FLV/FIV status, enlarged lymph nodes and/or intestinal issues will likely put lymphoma high on the diagnostic list. Any evidence of tissue masses where there shouldn’t be or enlarged organs visible on x-rays or ultrasound examinations make lymphoma even more likely. Michigan State Veterinary Diagnostic Laboratory does offer the PARR test that might be helpful in diagnosis. (read here) another test that might be helpful in that regard is called a microRNA test. A “liquid biopsy” test is in development for dogs that the manufacturers claim will detect lymphoma. They mention nothing about cats, and the value of the test itself is yet to be determined. (read here) But for now, endoscopy, ultrasound exams, CAT scans, biopsies and a current FeLV/FIV test are most commonly suggested.

What Treatment Options Do Veterinarians Have If My Cat Develops Lymphoma?

Lymphoma exists in two forms in cats, “small cell” lymphoma and “large cell lymphoma”. Small cell lymphoma is a smoldering, very slowly progressive (indolent) disease. (read here) In humans, it is broken down into many more subtypes than veterinarians are likely to. Cats with the small cell form of lymphoma respond dramatically to a combination of steroids (often prednisolone or dexamethasone) and oral chemotherapy drugs (often chlorambucil). Cornell University veterinary school mentions that they use that combination of medications to treat that form of lymphoma. They quoted hopeful cat survival time at 2–4 years.  Other veterinary oncological centers, at 2–3 years. Cats with the nasal form, 1 year. However, an Embrace Pet Insurance publication states that the average length of life of an insured cat, once lymphoma has been discovered, is 6–9 months. It does mention that young cats with the chest (mediastinal) form of lymphoma did considerably better than that when treated with radiation. The Embrace article does not mention how or where that data was obtained. 

Large cell lymphoma in cats is much harder to successfully treat. Survival time is often shorter. Large cell lymphoma is also more likely to result in intestinal obstruction, requiring emergency surgery. Radiation treatments are often added to the cat’s treatment plan, and the chemotherapy drugs used tend to have considerably more side effects than chlorambucil. Those drugs must be given by intravenous injection, often repeated weekly. Some that are suggested are cyclophosphamide,   vincristine, and doxorubicin. Cats taking those powerful medications need frequent monitoring for decreased WBC counts, anemia and kidney and liver heath. Cornell quotes lifespan when those procedures are followed at 4–9 months. They also state that when given prednisolone alone, cats generally improve for 2–4 months.  mentions in their promo that cats undergoing their CHOP chemotherapy treatment might live an additional 6–9 months. They, and VCA, also experiment dispensing lomustine to treat lymphoma, primarily because it can be given by mouth. In a UK study, the median progression-free survival time when lomustine was included was 61 days (range 16-721 days). (read here) I think that this is a good point for me to chime in with Bernie Rollin’s thoughts, which are the same as mine that “rescue protocols” like these for cats suffering the misery of cancer and other terminal diseases are a cruel abomination, akin to the experiments of Dr. Moreau.

How Expensive Might Lymphoma Cancer Treatment Be For My Cat? How Much Might It Cost?

NCSUCVM does not quote a price for the treatment of small cell lymphoma in cats. But I imagine that it would be similar to their palliative treatments for lymphoma in cats, which run $1,000 – $2,000. Neither chlorambucil nor prednisolone are expensive drugs. When it comes to intensive treatment for large cell lymphomas in cats, they recommend their CHOP protocol which, on their current website, runs $5,500 – $6,550. If they are going with their experiments with their CCNU aka lomustine for large cell lymphoma, they quote a price of $300 – $400 per treatment for a minimum of 5 treatments. Radiation treatments for a single area, such as lymphoma in your cat’s nose or chest, runs $4,500 – $6,500. If the tumor has already spread to multiple areas, radiation therapy runs $5,000 – $7,000. I do not know if that is for each radiation application or for the entire series when multiple treatments are provided. They add: “Cost estimates are based on individual appointments and the overall cost is dependent on patient response and does not include additional supportive care or hospitalization if required.”

Embrace Pet Insurance quotes the cost of lymphoma treatment in cats as “extending well beyond $10,000” when “heroic” methods of treatment are used. They say that diagnosis is typically ~$500, but can be considerably more, surgery typically $1,000 – $3,000, Radiation therapy $5,000 – $10,000, and “experimental” veterinary school treatments up to $15,000. Most pet insurance plans I know of, do not cover treatment that is considered experimental, investigational or beyond the standards of cat care in your area. You would have to call the insurance company you are considering enrolling your cat in and ask. PetsBest accident-and-illness policy claims data from Jan 2017 to May 2020 gave their average payment to cat owners for cancer treatments as $3,282.


Fibrosarcomas In Cats

The most common cause of superficial fibrosarcoma tumors in cats at a relatively young age is overzealous vaccinations, although vaccines are not the only possible cause. (read here) Fibrosarcomas most often occur just under a cat’s skin. The most common area that they occur is on the nape of your cat’s neck, between the shoulder blades, on the nape of your cat’s neck or in is upper torso area – the favorite sites for veterinarians or their technicians to give vaccines.Cats have a very robust inflammation process to injected foreign substances, much more so than dogs or people, and chronic inflammation is one prelude to cancer. Even injections of long-acting drugs and implants have been known, on very rare occasion, to stimulate fibrosarcoma formation. (read here,   here,   here & here) You can read more about fibrosarcomas in cats here. They are often referred to as vaccine-associated sarcomas (aka VAS, VSS, FISS or ISS). This is a heartbreaking condition because it often occurs in cats at a relatively young age. When related to vaccination, it is the only tumor I know of that is preventable. Fibrosarcomas in cats, discovered early, can sometimes be treated successfully with surgery. But that surgery must be very aggressive, removing a large amount of surrounding tissue. It is said that over time, some of these tumors have cancerous cells projecting much as 13–15 cm (~5 – 6 inches) distance from where the injection was given. Veterinarians first noticed skin tumors in cats associated with vaccination in the 1990s. It wasn’t the virus or bacteria in those vaccines that were thought to be the cause. It were the potentiating ingredients (adjuvants) they contained that were suspected. The feline vaccines of today contain fewer or no adjuvants.  Boehringer Ingelheim’s Purevax® feline vaccines, including their one and three-year rabies vaccines, are adjuvant free. Merck, Boehringer Ingelheim’s competitor, correctly points out that no one has ever proven that a non-adjuvanted vaccine is safer for your cat. That the frequency with which fibrosarcomas develop is cats is “speculative” and that non-cancerous lumps at vaccination sites (granulomas) can be mistaken for fibrosarcomas. Merck also says that there is no evidence that the incidence of fibrosarcomas has gone down since Boehringer’s vaccines were introduced. (Boehringer bought out Merial, the actual developer of much of the adjuvant-free technology). Merck goes on to points out that your cat’s individual genetics is probably involved. That is probably true too, but begs the question as to whether one brand of vaccine is safer than another. They quote a British cat study that states that “no vaccine can be assumed to be risk-free in a susceptible individual.” (read here)

The American Animal Hospital Association (AAHA) now recommends that rabies vaccinations be given to cats in their lower right rear leg and that a three-year duration vaccine be used. That Feline leukemia vaccinations be given in the cat’s left rear leg below the knee – three times, twice as a kitten and then at 12 months with no need for further FeLV vaccinations. That the panleukopenia/herpes1/calicivirus (3-way) be given in the cat’s right front leg below the elbow. Others suggest that those vaccinations be given as close to the tip of the paws as possible. That might allow a cat that develops an injection site fibrosarcoma to have no more than one or two toes removed. All of these vaccines are also effective when given subcutaneously in your cat’s tail. (read here) Most cats will put up with that. If not, then subcutaneously in the cat’s rear ventral abdomen. None of those locations make the development of fibrosarcomas less likely, but the tail and lower legs give the option for amputation, should a tumor form, and there is usually sufficient extra skin on the lower side of your cat’s abdomen to close the large incision needed for tumor removal. Traditionally, these vaccines had a volume of 1 ml. Boehringer now makes feline vaccines that are 0.5 ml. If that makes fibrosarcoma formation less likely, more likely, or has no effect, remains unknown. 

Another effective strategy to avoid fibrosarcomas is to not have your cat vaccinated so frequently. (read here) Vaccines, routinely given throughout your cat’s life, are a low-stress money earner for veterinarians and the companies that produce those vaccines. But there is no evidence that they need these boosters once they were immunized in their youth because none of the virus they contain rapidly mutate like COVID or human Flu do.  I never revaccinate a cat that formed a hard bleb or lump at a vaccination site – even if it appears to be gone within a week or two. But then, I rarely see these blebs and no client of mine has ever experienced a cutaneous fibrosarcoma in their cat. Perhaps that is because I vigorously massage the injection site after injection to distribute the vaccine contents over a wider area. Perhaps I have just been lucky. Most vaccine-related tumors appear within ~4 years after vaccination. It is always wise for your vet to remove and submit to a pathologist any bump or lump that persists on your cat for more than a month – sooner if it continues to grow. That excludes fight wound accesses. Your vet can tell an abscess or scar from a tumor by its look and feel, but not a tumor from a granuloma. 

To surgically cure a cat of VAS, every single malignant fibroblast needs to be surgically removed or killed by radiation or chemotherapy. Before attempting to remove VAS fibrosarcomas most vets would want to do x-rays to be sure the tumor has not spread to other sites. They might also suggest an injection of a Boehringer product, Oncept®When physically possible, about 2 inches (~5 cm) of what appears to be normal tissue needs to be removed completely around the tumor. That is because that “normal” area might already be infiltrated by cancer cells. It may be impossible for your surgeon to remove that much tissue. That is why post-surgical radiation treatments of the area are often suggested. Some vets do that before the surgery, some do it after. Even if radiation does not kill all the fibrosarcoma cells, it might at least slow the progression of the disease. A veterinary oncologist might suggest follow-up chemo.

Benign fibromas are said to occasionally occur. I have never seen one, (read here) and various other tumor types can form in superficial areas. Basal cell carcinomas are one of them. When they occur, it is often in a Persian cat. Surgical removal is the preferred method to treat them as well. Fatty tumors (lipomas) are quite rare, but possible in overweight cats. Skin melanomas have occurred as well. 

How Expensive Might Fibrosarcoma Treatment Be For My Cat? How Much Might It Cost?

Embrace Pet Insurance estimates the cost of fibrosarcoma diagnosis for your cat to typically be less than $500. Imaging and biopsies to define the tumor’s likely borders could run $2,000 or more. For a typical surgeon’s attempt to remove the tumor, they estimate at $1,000 – $3,000. The cost of post-surgical chemotherapy they estimate at $1,000 – $5,000. Radiation therapy, either on its own or proximate to surgery, they estimate at $5,000 – $10,000. But they also mention that the prognosis for all feline fibrosarcoma patients, even those that receive these treatments, is poor. They state that over 70% of the cats will relapse within the first year. For those cats that developed fibrosarcomas subsequent to a vaccination, their estimated relapse figure jumps to more than 90%. Embrace “farms out”  the writing of some of their pet health articles, in which case their estimates of costs and chances of relapse might not be based on the Company’s claims history, but only on the experience of the particular veterinarian who wrote the article. 

NCSVS lists various skin sarcoma removal surgeries in cats as costing $3,000 – $5,000. Their charges will be more if the tumor exists in a difficult area to approach. They suggest that post surgical survival is likely to be 3 months to 2.5 years. In another text, they w-rite “up to 2.0 years or more”. They note that treatment might also require a CT scan in order to make correct surgical decisions. Pre or post surgical radiation therapy is estimated to cost another $4,500 – $7,000. Intravenous chemotherapy costs $400 per treatment. Oral chemo medications typically cost $300 – $400 per month. Electrochemotherapy costs $1,000 – $1,200 per treatment. They also give you the option of up to 6 Feline IL 2 Immunotherapy vaccine injections (that is probably the Oncept®I mentioned earlier, or something similar). The teaching hospital at the University of Florida suggests that cats undergoing combining surgery, chemotherapy and radiation therapy at their facility experience a “tumor-free” time of 18–24 months before they relapse. Those treated only with surgery, considerably less. 



Tumors In Your Cat’s Nose | Nasal Tumors

Sometimes tumors form in very hard to get to places in your cat. That is the case with nasal and nasal/sinus tumors. Nasal tumors are not that common, they are said to only account for 1% of the body-wide tumors that cats develop. The two most common types of tumors that form there are lymphomas and carcinomas. Other cancer types occasionally occur, but they are much rarer. The chances of one or the other is about 50-50. The approaches available for veterinary surgeons to reach some of these areas where tumors form can be very challenging. The early signs that something is amiss are persistent drainage – often, from only one nostril, sneezing and vomiting. Occasionally, the discharge is tinted with blood. In one study, about 24.5% of middle-aged cats, experiencing persistent nasal drainage, were found to have a nasal tumor. (read hereOf course, there are very many non-tumor reasons that can be responsible for those signs too: an upper respiratory tract infection, a foreign particle in the cat’s nostril, allergies, sinusitis, a tooth root infection, a dusty environment, fumes, or aerosol sprays are some of them. When nasal tumors become more advanced, a small budge and some crusting might be visible on the surface of your cat’s nose. Some report that the average age that a cat is diagnosed with a nasal tumor is 10 years. The only good thing about the common nasal tumors is that, for extended periods of time, they rarely spread to other areas of the cat’s body. If surgery is contemplated, your veterinarian must face entering very narrow passages that are very close to critical structures like the eyes, facial nerves and brain. As I mentioned, some of these tumors, when advanced, extend into the cat’s sinuses. Also, although nasal tumors rarely spread to other parts of your cat’s body, they are locally invasive. That means that a large portion of the tissue surrounding the tumor that appears to be healthy needs to be removed as well. If attempted, laser surgery is most likely to result in the least blood loss in this highly vascular area. If one is fortunate enough to detect a nasal tumor when it is small and approachable, one might attempt to destroy it with cryosurgery. But it is rare to encounter one that gives your veterinarian that opportunity. Cryosurgery is very effective when dealing with benign feline nasal polyps. But in most cases, the chances of your veterinarian successfully removing all of a nasal tumor are very small. 

That is why veterinary specialists are more likely to recommend radiation treatment. Or, if they should attempt surgical removal, suggest the cat undergo radiotherapy afterwords. A period of survival after nasal radiotherapy in cats is often quoted as 6 to 18 months. Other sources say a year. But that is highly dependent on the stage the tumor is at when first detected. Survival also appears longer when the tumor is a lymphoma rather than a carcinoma. It also appears that the power at which the x-ray source is set to is important too, a dose of ≥32 Gy of radiation energy appeared most effective. (read here). There are veterinarians who still recommend a modified “CHOP-LITE” chemotherapy (doxorubicin, lomustine, and prednisone), alone, or subsequent to radiation and/or surgery when the tumor is known to be a lymphoma. I would never subject my cat to that degree of experimentation and pain. Radiation treatments and chemo can be repeated when relapses occur. But I believe that most owners would opt for palliative treatment for the cat they love at that point to keep it as comfortable as possible and not put it through another round of stress with doubtful outcome. Things like pain relief, tempting home prepared meals, appetite stimulants, plenty of hands on contact, and nebulization treatments. I know of some veterinarians that incorporate imiquidod cream in their treatment plan.

Tufts Veterinary School and 16 private US veterinary oncology centered, in hindsight, reviewed the records of 96 cats that they treated for nasal lymphoma, either with radiation therapy, or with chemotherapy, or with both. The median survival time after any of those treatments was 172 days, although some of the deaths were probably not related to their nasal lymphoma. Anemia and/or refusal to eat, when present at the time of admission, predicted a poorer outcome. The median survival for those that received radiotherapy alone was 192 days, compared to 116 days in those that did not receive treatment. However, between the three treatment types, radiation, chemo or both, no difference in longevity was found. (read here)

How Expensive Might It Be To Treat A Nasal Tumor In My Cat?

When a nasal tumor is detected in your cat, your primary care veterinarian is likely to refer you to a veterinary oncologist. There you are most likely to be billed for a biopsy to determine the cancer type, perhaps lymph node aspirates to see if the tumor has spread, radiographs, rhinoscopic endoscopy, perhaps CT scans or MRI of your cat’s nasal cavity, chest and abdominal area to see the extent of the tumor and whether metastasis has already occurred. If you did not bring, complete blood work results performed at your local animal hospital, that will be requested too. A FLV/FeLV test might be requested, if not recently performed as well. Your oncologist will probably want to perform ultrasound examinations, even if some were already performed. At, that point, depending on the results, you might be offered 1–3 sessions of stereotactic radiation treatments  (=pinpoint) for your cat. Perhaps many more if conventional radiation generators are used. Later, perhaps chemotherapy to slow your cat’s decline or palliative treatment, medications to stimulate your cat’s appetite and relieve pain and decrease nasal inflammation. Some vets have combined minimally invasive endoscopic nasal surgery to reduce tumor size and afford the cat temporary relief. (read here) Some veterinarians believe that anti-inflammatory drugs in the NSAID class might actually retard the growth of these and other tumors. (read here) Others experiment with Palladia™, an oral anti-cancer medication approved for mast cell tumor treatment in dogs. 

NCSUCVM oncology department gives the price of radiation treatments for nasal tumors as $4,000 – $8,500. That includes the radiation oncology consultation, a CT scan to plan the treatment, radiation therapy planning, quality assurance testing, anesthesia and radiation treatments. If a CT scan needs to be performed, that generally adds about $1500 to the bill. They note that the goal is not a cure. It is to improve the quality of your cat’s life and prolong it as long as possible.


Tumors In Your Cat’s Mouth1 | Oral Tumors

The lining of your cat’s mouth and the surface of its tongue are similar to the lining of its nose. So, as you might suspect, they occasionally form the same tumors. But in this case, carcinomas greatly outnumber lymphomas. When they occur, like most tumors, it is generally when your cat is already elderly. The most common type is a squamous cell carcinoma. Unfortunately, one with poor outcomes because it is highly malignant. Cornell considers it the fourth most commonly type of feline cancer. Squamous cell carcinomas are said to account for ~90% of the tumors that form in the mouths of cats. Veterinarians are uncertain why one cat develops these tumors and another doesn’t. Genetics, certain flea collars, poor dental hygiene, eating primarily canned cat food or feeding canned tuna have all been implicated. (read here) Two statisticians, given permission to thumb through the records of Tuft’s veterinary school, also came to the conclusion that exposure to pollutants such as cigarette smoke might increase the probability of these tumors. It was a small number of cats whose records they were able to examine, and the effects of smoke appeared minimal. The same study found that flea bathes made oral tumors less likely to occur. I suppose these were in-and-out cats, and no one knows what else they were exposed to in their wanderings. The feline leukemia and feline immunodeficiency virus status of these in-and-out cats was never mentioned. (read hereVIN, the veterinary information network, reports that the average age for oral tumors to develop in cats is 12.5 years. A common place for these tumors to begin is adjacent to your cat’s teeth or under its tongue. Those are areas often associated with chronic gum inflammation, loose teeth and halitosis. Chronic inflammation is an enabler of cancer. (read here) The best preventative for that is beginning your cat on hard treats early in its life. (read here)

As with nasal tumors, your veterinarian’s options are limited once an oral squamous cell carcinoma has been detected. Fewer than 10% of cats with this diagnosis survive more than a year. – despite the veterinary care of your favorite general practice veterinarian or the tumor specialist he/she sends you to. These tumors often invade the tissues and bone adjacent to them. There exist veterinarians who have gone as far as removing the cat’s jaw(s) and portions of its skull in attempts at halting the tumor’s progress. This is another good point for me to be an advocate for your cat and ask if you are consenting to these procedures for your emotional benefit or for your cat’s benefit. I, like Bernard Rollin see such surgery as exceedingly cruel. Akin to the vivisection of animals that H.G. Wells attempted to draw public attention to. Radiation and chemotherapy are other options. The median survival time after radiation is said to be ~5 months. Many veterinarians believe that chemotherapy is not worth the effort because it has not reliably increased cat lifespans and so commonly causes major side effects. Nevertheless, your state’s veterinary board requires veterinarians to mention those options to you. Veterinarians like me sometimes face the guilty feelings of cat owners whose grown children question end of life decisions for your cat. That might be due to their childhood memories of the good times they had with the cat, or just because they do not grasp the gravity of the situation or deal with it on a day-to-day basis.  and protest when you decide it is in your cat’s interest to send your friend on to Heaven. Physicians call it the California syndrome. Much rarer types of cancers that occur in the mouth of cats include melanomas, fibrosarcomas and adenocarcinomas.

How Expensive Might It Be To Treat An Oral Tumor In My Cat?

It would be quite similar to the costs of treating the nasal tumors that I discussed a bit higher up on this page. 


Mast Cell Tumors In Your Cat

Mast cell tumors (MCTs) do not occur as frequently in cats as they do in dogs. Mast cell tumors are said to account for 2-15% of all the tumors that cats develop. (read here) Some consider them the second most common skin tumor of cats. (read hereWhen MCTs are located on the skin of your cat, they are more likely to be benign or only moderately malignant and successfully removed by your veterinarian than they are in dogs. These tumors tend to be pinkish in color. They could easily be mistaken for a bug bite. Their most common location is on the cat’s head and/or neck, but they can appear anywhere on its body. MCTs are said to be the most common splenic tumor, the second most common skin tumor, and the third most common intestinal tumor occurring in cats. (read hereThe average age at which mast cell tumors are discovered in cats is ~ten. But they have occurred in cats as young as 4 years. Biopsy of any skin lumps you find on your cat is very desirable when your veterinarian is suspicious that it might be a tumor. It is the only way to identify a mast cell tumor with certainty and formulate a treatment plan. Once your veterinarian knows what he/she is dealing with, a generous portion of tissue surrounding the tumor may need to be removed as well. Although appearing normal, it too might contain outlier cancerous cells.  Siamese cats are said to lead the list in mast cell diagnosis. Veterinarians do not know why.

What Are My Cat’s Treatment Options When A Mast Cell Tumor Is Discovered?

Hopefully, your cat has the option of having the complete tumor, and a liberal amount of the tissue that surrounds it, surgically removed. When a superficial mast cell tumor biopsy report indicates that the tumor is highly malignant, or when the MCT is located internally or has already metastasized, oral lomustine was found to slow mast cell tumor growth.That study gathered its information from 15 veterinary school clinics and feline cancer treatment centers in the United States. Of the 38 cases they located, 26 had mast cell tumors of the skin. Seven had MCTs of the lymph nodes associated with their intestines. Two had digestive tract (gastrointestinal) MCTs. Two had liver MCTs. And 1 had multiple internal organs affected. (read here) That data most likely reflects the general likelihood of where feline mast cell tumors in cats will be discovered. But you need to consider that many more internal MCTs are less likely to be noticed in their early stages than those that occur on the skin.

When a mast cell tumor cannot be removed in its entirety, an oral chemotherapeutic medication, imatinib, (Gleevec®|Glivec®) has shown promise in treating MCTs and, perhaps, fibrosarcomas and squamous cell carcinomas in cats as well. (read here, here,    here,   here & here)

Prednisolone or dexamethasone, given orally or by injection at high-end doses to cats, was once reported to be effective in shrinking mast cell tumors in approximately 23% of cats to whom it is given. That effect might be temporary. Corticosteroids, such as those, appear to be toxic to mast cell. So, they are often incorporated in mast cell treatments. In one report, a cat given a combination of prednisolone, and chlorambucil had its internal mast cell tumors go into remission. But few veterinarians believe that that is likely to occur. (read here)

In their promotional material websites, many commercial veterinary centers specializing in oncology do not differentiate their mast cell treatments for dogs, from their mast cell treatment plans for cats. They do mention that, in many cases, post-surgical radiation is suggested. Some propose up to fifteen, 30–45 minute post-surgical radiation treatments, one a day, excluding weekends. For that, your cat must be anesthetized. Internal mast cell tumors require a CT scan to target radiation. Other veterinarians believe that mast cell tumors are only moderately sensitive to radiation therapy, and that radiation therapy is not a good choice when the tumor has spread to other areas of your cat’s internal organs. In those cases, if you elect treatment, vinblastine,   vincristine,   lomustine (aka CCNU),   cyclophosphamide or hydroxyurea are the drugs commonly suggested. Also, often included in treatment, is the Palladia™ that I already mentioned regarding nasal tumors, particularly if the cat’s mast cell tumor is cKIT mutation positive. 

How Expensive Might It Be To Treat Mast Cell Tumors In My Cat?

Your cat will need fine needle or tissue biopsies to confirm that it is a mast cell tumor (mastocytoma) and determine how malignant it is (its “grade”). It will need a standard veterinary blood chemistry test, a CBC and a urinalysis.  If tumors are suspected internally – and even if they are not – most vets would require ultrasound and x-ray examinations. Those tests are necessary to access your cat’s general health and the likelihood that it could tolerate anesthesia, surgery or chemotherapy. Many vets administer Benadryl antihistamine prior to surgery, since traumatized mast cells emit histamines. Surgery to remove mast cell tumors of the skin is often successful. A bit less so when the cat’s spleen is involved. 

The NCSUCVM does not quote prices for mast cell treatment in cats, only for dogs.  However, the costs should be similar. Single internal mast cell tumors or multiple skin mast cell tumor removal in dogs costs $2,000 – $4,000. Post-operative radiation therapy costs $4,500 – $6,000. Palliative radiation therapy runs ~$1,000 – $2,000. Vinblastine or lomustine chemotherapy costs $300 – $400 per treatment. The costs of these drugs factor in to what you will be charged, so cats should be on the lower cost end. Palladia treatment for dogs runs $300 – $650 per month. Palladia costs are pet-weight determined as well. Corticosteroids, when dispensed, run $30 – $200 per month, which includes blood monitoring for side effects. “Cost estimates are based on individual appointments and overall cost is dependent on patient response and does not include additional supportive care or hospitalization, if required.”


Breast Cancer In Cats | Mammary Gland Tumors

If your cat was not spayed when it was young, a few, around the age of ~13, will develop breast cancer. A mammary gland cyst might mimic a tumor. Only a biopsy submitted by your veterinarian can tell the difference. But if it is a tumor, and most are, it will almost always be a carcinoma or an adenocarcinoma. Unfortunately, unlike dogs, the vast majority of feline mammary tumors are malignant. They begin as small lumps or nodules in one or more of your cat’s mammary glands. With time, and as they grow in size, the tumors sometimes form draining ulcers (fistulous tracts). Eventually, metastasis to the cat’s lymph nodes, which drain the mammary glands and the lungs, is common. Previous use of megesterol to control eosinophilic dermatitis, for birth control or inappropriate urination appears to predispose cats to these tumors. Whether or not you allowed your cat to have kittens does not appear to matter. If surgery is preformed on these cats as soon as possible after a mammary gland tumor is noticed, success is more likely if all of your cat’s mammary glands are removed. That often requires several individual surgeries due to limits in the amount of abdominal skin available for your veterinarian to close the surgery incisions. Radical surgery of this type, soon after discovery, is said to be successful in about half of the cases. When performed later in the disease, post surgical survival time is about 150 – 180 days. Owners often decide to euthanize these cats before that because of the poor quality of the cat’s life. Radiation and chemotherapy have not been particularly successful in curing or slowing the growth of these tumors. Another very good reason to hesitate surgery or chemotherapy is your cat’s age. Read about that further along.


Do Cats Develop Other Types Of Tumors That You Have Not Mentioned?


Lipomas are benign tumors of subcutaneous fat tissue that might be confused with mammary gland cancer when they occur on your fat cat’s lower abdomen. A needle aspirate, performed by your veterinarian, will tell the difference. Generally, they need not medical treatment. But they are a warning that perhaps your cat would benefit from a lower calorie diet. Obesity often precedes diabetes in cats. Cornell reports that fat cats are up to four times more likely to develop diabetes than cats of normal weight.

What I discussed were just the most common cancers that cats face. Any cell in your cat’s body that divides has the potential to produce a tumor. There are about 200 different cell types in your cat’s body, and pathologists give a name to every one of them when they become cancerous. Cells that divide rapidly throughout your cat’s life, such as glandular cells and cells produced in your cat’s bone marrow, are the most likely to be the ones that develop cancer. The Merck Veterinary Manual, available to you online, is the best way to learn more about them. As to their potential treatments, your cat’s options do not differ greatly from those for us humans that you will find on Wikipedia.



How Does My Cat’s Age Factor In When I Make My Decisions Regarding Cancer Treatment?

As your cat gets older, just like us, chronic health issues are more likely to be present. Things like, chronic kidney disease,   hyperthyroidism,   digestive tract issues. heart and hypertension-related problems, chronic dehydration and cognitive rigidity (more set in their ways) that might make administering medications more challenging.  Frequently, more than one of those issues will be present, some of them already requiring medications. Veterinarians call them comorbidities when deciding on an appropriate cancer treatment plan. Some of the treatments for comorbidities, particularly kidney or liver issues, can be at odds with drugs used to fight cancer. (read here   here  & here) They are also the reason your veterinarian will want a thorough, general health checkup for your cat before weighing your treatment options and the chances for success. You know your cat’s temperament and abilities better than specialists, who tend not to focus on comorbidities. What, in theory, could be beneficial in combating cancer, can be incompatible with your cat’s other real-life issues. 


Keeping Your Cat With Cancer Happy

Your cat was blessed by the Creator in that it does not fear the future or dwell on its illnesses. It does not worry about the passage of time or where it will spend eternity. So if they even consider it, they face death with considerable peace. Veterinary medicine has made tremendous strides in delaying the death of our pets. My other articles explain strategies your veterinarian uses to do that. But would your cat want your veterinarian to do all the things that are scientifically conceivable to keep it alive? My feeling and Bernie Rollin’s feeling are that it would not. Would you be doing those things for your pet’s happiness, or for your happiness? As I mentioned, sometimes the hardest decisions you must make in your life are the ones that will hurt you the most. The way to your cat’s happiness is through a familiar, loving environment, your presence and touch, and a savory diet.

I cook and taste everything I feed to my pets. If it doesn’t have a rich, meaty flavor, it goes to the trash. So I don’t suggest you feed your cat any of the deceptive “Onco cancer diets” that specialty dog food companies peddle online and through veterinarians. There is zero legitimate, independent, science supporting their claims. A major producer of that food line and one of their contractors did pay for a positive study, but they only point to the fact that it contains higher quality ingredients than low-quality cat foods, so it tastes better and that it is nutritionally complete. (read hereI hope that you and your loved ones never develop cancer. But if it happens, is your oncologist going to go to the back room and come back with a cart full of canned or sacked food that you have to eat for the rest of your life? You will do a much better job cruising the meat isles of your neighborhood supermarket and preparing your cat’s diet on your stove top. When it no longer accepts what it once enjoyed, consider an appetite stimulant such as mirtazapine. I have tasted Elura appetite stimulant for cats. If your cat shows displeasure with its taste (as I did) don’t give it.


Beware of purchasing products online that claim to cure cancer. They do not work. Beware of the false empathy of people with impressive degrees urging you to do things that are really not in your cat’s interest. That goes for any Google Ads that might sneak onto my website as well. The Googlebot treats the honest and the dishonest ads equally. Best wishes to you and your cat. RSH

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