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Cancer Therapies for Cats


If your cat has been diagnosed with cancer, your veterinary health care team has likely already counseled you about the type of cancer it is, the best treatment options available, your role as home caregiver, and the expected prognosis. Here, we will review what you can expect from some common types of cancer treatment and describe the supportive care offered when a decision not to treat has been made. Treatment may require considerable time and expense, and it is important to make sure all of your questions are fully addressed before a decision about therapy is made.

Modern state-of-the-art treatment regimens for feline cancer have significantly improved outcomes while reducing the nasty side effects of some of these therapies. We now have a better understanding of the role of pain management and nutritional support as adjuncts to successful cancer management as well. As our lucky cats live a much longer life span, cancer has become a more commonly encountered condition. As part of the health care team acting for the welfare of your cat, the better you understand what is going on, the more helpful you can be to your cancer kitty.

There is no single cure for cancer, and each patient needs to have their treatment plan carefully customized. Treatments are often prescribed in combination. This helps to target the cancer most effectively, while minimizing side effects. Some of the options are discussed below.

Radiation Therapy for Cat Cancer

Not every veterinary hospital has the facilities for this type of treatment, so referral to a regional specialist facility or veterinary college may be necessary. Side effects from radiation therapy are most commonly due to “burns” of the tissue in the vicinity of the beam focus point at the tumor. If the tumor happens to be very near a delicate structure, this can become a serious side effect, but often adjacent tissues gradually regenerate without any long-term health consequences. This treatment modality usually just renders the tumor cells unable to reproduce, so tumor shrinkage may take a while. Following treatment, over time as these cells reach the end of their lifespan, they die off and none replace them. This will de-bulk the cancer. Inoperable tumors are most commonly selected for radiation therapy. Treatments will be spread out over time and given in partial doses to help reduce burns. Anesthesia is done while the treatment is carried out to prevent patient movement.

Chemotherapy for Cancer in Cats

This is a treatment option with very well-known side effects in people. The same side effects may occur in cats. The current strategy is to give different agents at low frequency and dose in combination with other anti-cancer agents acting by a different mechanism within a structured protocol. The drug protocols are administered over a long time interval to help the cat cope with the effects. This strategy keeps tumor cell killing activity high, while reducing side effects such as nausea, vomiting, poor appetite, irritation at the injection site, low white cell count leading to poor immune system function, and lethargy.

The way most chemotherapy agents work is to kill cancer cells because they are dividing faster than normal body cells. This means that more aggressive cancers which divide quickly often respond well to this treatment modality. Unfortunately, many of the above listed side effects are due to the fact that normal body cells also divide. Cells of the gut and immune system, particularly, are actively turning over in the normal animal, so they often get “caught in the crossfire” of chemotherapy, resulting in unpleasant side effects.

Surgery for Cancer in Cats

Surgical removal of lumps is a commonly used treatment for many types of cancer in cats, especially external ones. Laser, radiosurgery, cryotherapy, or the traditional scalpel all may be used to remove the tumor. The most difficult aspect of this treatment is to determine how far out from the obvious outline of the lump that cancer extends into surrounding tissue. The surgeon will normally take out an area much larger than the lump because of these microscopic tumor extensions, so that is why you see an area so much larger than the original lump sewn up afterwards. The tissue is sent to the pathology lab after removal. This allows microscopic examination of the tissue margins to be carried out. This step will help confirm that all of the diseased tissue was removed. It is not always possible to completely remove a lump, and so other modalities will be used to help clean up the remaining cancer cells in those cases.

Adjunctive Care for Cancer in Cats

Nutrition for the cancer patient is very important. Because of the stresses of the treatment on top of the demands of the disease, extra nutrition must be provided. The diet must be of high quality and easily digestable. Sometimes, extra treats with yummy smell and taste are put in with the high quality food, or hand feeding is done to help encourage the appetite. Cats with cancer, or those undergoing treatment for cancer, often have very poor appetites and so sometimes appetite stimulant medication is required, or even tube feeding provided.

Nursing care is important as well. At home and at the hospital, passive manipulation of joints or massage may be needed, or turning the patient over regularly may have to be done if the cat is weak. Soft bedding is essential if the patient is not mobile so that sore spots do not form. Help with cleaning up after elimination may be necessary if box behavior is reduced, and litter boxes with very low or no sides may need to be offered. Daily grooming will need to be provided by the caregiver because often the cat is too depressed to groom. A kitty may even need a chin wash after meals since food and water may remain in the fur around the mouth if self-grooming is absent. A low stress, draft-free, warm environment, with a double dose of TLC is essential!

Pain medication is also used to help the cancer kitty feel as comfortable as possible. Not many medications are safe for long-term administration in cats, but your veterinarian will prescribe these drugs as needed, perhaps on a periodic or tapering dosage regimen.

Palliative Care for Cats with Cancer

Sometimes, the decision is made that you will not treat your cat's cancer. Whether the cancer is too advanced to respond to therapy or other factors lead to selection of this course of action, this is a viable option in some cases. Not all cancers are treatable at the time of diagnosis, or in the case of debilitated cats, definitive treatment may be too stressful. For some cats, hospice type care provides some quality time with the goal of helping these sick cats stay as comfortable as possible for as long as possible.

This care option requires appropriate ongoing nursing care, pain management, nutritional support, perhaps some complementary therapy, and an open dialog with the veterinarian to determine when the time is right to consider a euthanasia decision.

Though managing a cat with cancer can be emotionally draining, costly, and time intensive, there are many opportunities available these days to help your cat enjoy the best quality of life possible for as long as possible. If it makes sense for the individual patient and owner, it is nice to take advantage of the advances in therapy that can frequently provide cancer remission or sometimes even a cure for this complex disease.

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