Cancer Treatments for Dogs and Cats

Medical articles
Sad Beagle Looking Out the Window

Cancer is a common diagnosis of older dogs and cats and accounts for upwards of 50% of deaths in pets each year. According to the American Veterinary Medical Association, almost half of dogs over the age of 10 will develop cancer. While there is less information on the rate of cancer in cats, it is understood that they become more susceptible to developing certain cancers like lymphoma as they age. That's why it's important to plan ahead and invest in pet insurance for cancer. Finding out that a pet has developed cancer may leave you with many questions about what needs to be done next and how best to care for him or her. Because different types of cancer act on different parts of the body, and in many different ways, treatment will vary. Surgery, radiation, chemotherapy, and newer forms of immunotherapy are the most common methods of treatment. These methods, depending on the type and severity of cancer, may be performed together or alone. If a pet is suspected to have cancer or has been recently diagnosed with cancer, an in-depth discussion with your veterinarian, as well as a consultation with a veterinary oncologist, are good places to start.


A biopsy to remove a piece of the tumor or cancerous tissue will likely be needed to diagnose the type of cancer. In some cases, removing the entire tumor may cure the cancer. A pathologist can examine the tumor cells to determine the type and severity of cancer, and may be able to help determine if more surgery or other treatments are needed. For cancers that cannot be completely removed, “debulking,” or removing as much of the diseased or cancerous tissue as possible, can at least help improve the pet’s quality of life and may help slow the cancer’s spread.


With some types of cancer, radiation may be needed to help shrink the tumor or decrease the pain associated with the cancer’s growth. It can also be used when microscopic cancer cells are left behind after surgery to kill off the remaining cancer and prevent it from spreading. Side effects can include damage to the surrounding tissues. This damage may cause an effect similar to that of a bad sunburn or, in more severe situations, may cause ulceration or sores. These side effects can be painful, but medication is available to help ease the pet’s discomfort if needed.


With some types of cancer, chemotherapy may be needed to shrink tumors, slow cancer growth, or reverse the cancer’s development. Often, chemotherapy drugs affect rapidly dividing cells, so some of the body’s normal cells that grow quickly may also be affected. These cells include bone marrow cells and cells within the intestines. The good news with chemotherapy is that the side effects seen in humans are much less common and much less severe in pets. The hair loss, nausea, exhaustion, and gastrointestinal (GI) upset humans experience are rare in pets. This is possibly because the amount used in veterinary medicine is at a much lower dose and combinations of chemotherapy drugs used are slightly different.


Immunotherapy treatments in veterinary medicine are relatively newer than surgery, radiation, and chemotherapy treatments. These treatments use the pet’s own immune system to help fight the cancer cells. An example of immunotherapy in dogs is the melanoma vaccine, which is a vaccine targeted towards parts of malignant melanoma cells.


Other options for treating cancer involve keeping the body healthy without helping the cancer grow. A diet change geared towards more nutrients and a balance of higher proteins and fats as well as appropriate vitamins, antioxidants, and omega fatty acids may be recommended by your veterinarian. Pain control is also very important for pets with cancer. For some cancers, medications such as a COX inhibitor like piroxicam, which is a nonsteroidal anti-inflammatory drug (NSAID), may be useful for its anti-cancer effects. Steroids such as prednisone have been shown to be beneficial in improving a pet’s quality of life with certain types of cancer as well. Your veterinarian will be able to help determine if some of these options will be helpful for the pet. He or she may also be able to offer suggestions for other treatments that may help a pet deal with the side effects of cancer, such as medications to help with GI upset, nausea, or appetite improvement. Be sure to call your veterinarian with any new changes or concerns.