Cancer In Dogs and Cats

Unfortunately our dogs and cats get many of the same types of cancer that humans get.  


The symptoms of cancer vary depending on the type of cancer and the location of the disease. Typically we either see a lump, bump, or nodule on the surface of the skin, under the skin, or we feel a mass in the belly of our patients. We can also find evidence of cancer on x-rays and ultrasounds. Weight loss, decreased appetite, vomiting, diarrhea, and lethargy are other common presenting complaints.  Any lump that is felt should be examined by your Veterinarian. Not all lumps and bumps are cancerous, but the earlier they are examined, the more options there are available for treatment. You can’t tell if they are benign or malignant without sampling them.


The diagnosis of cancer relies on a variety of tests, but it is ultimately a biopsy or a sample of the tissue that confirms the diagnosis. If there is a mass that we can feel, it may be sufficient to place a small needle into the mass to retrieve some cells for analysis. This can usually be done without sedation, and with very little discomfort. The sample can be examined immediately, and sent out for analysis if necessary. If an aspirate can’t be done, then we would need to use other techniques to get larger samples which may involve surgery and sedation or anesthesia. Blood testing, ultrasound examinations, and radiographs (x-rays) help us to localize the problem and to plan our biopsies.

Although we typically see cancer in our older patients, there are cancers (like bone cancers) that we see in young dogs and cats. There are certain breeds of dogs and cats that tend to get cancer more frequently. The most common cancers that we see in dogs are mast cell tumors and lymphoma. In cats, lymphoma is the most common cancer that we see.harry 2

Prognosis and Treatment

The prognosis and the treatment options vary depending upon the type of cancer and the location of the disease. Staging of the disease with x-rays, ultrasound, and blood work helps to determine the extent of the problem. If the tumor is in a location where it can be removed with surgery, and it is the type of cancer that does not tend to spread quickly, surgery is the first consideration. If the cancer is a systemic problem, or there is evidence in multiple locations that can’t be dealt with surgically, then radiation and chemotherapy can be considered. Surgery can be curative. Generally radiation and chemotherapy are employed to keep the disease in remission for as long as possible.

Chemotherapy sounds scary, and it needs to be treated with great caution and respect. It can, however, greatly improve the quality of life for our cancer patients. Our lymphoma patients, for example, can survive for 9-12 months or more with treatment. We use many of the same drugs that are used in humans. We try very hard to avoid side effects by adjusting our doses and using supportive care including anti-nausea medications. We aim to control the disease without compromising quality of life for our patients during their treatment.

Treatment may involve decisions about quality of life and keeping your beloved family member comfortable for as long as possible. We are available to help with these difficult discussions and decisions.