Unfortunately, cancer is something that we are all too familiar with in pets. Most commonly seen in our senior and geriatric pet populations, cancer is essentially the abnormal growth of a specific cell type and can occur anywhere in the body. It often presents as a lump or mass commonly referred to as a tumor.

Cancer can be divided into two different categories: benign and malignant. Benign cancers grow relatively slowly and in a very localized manner. On the other hand, malignant cancers tend to be much more aggressive and are far more likely to metastasize or spread to other parts of the body.


By far, the most commonly diagnosed cancer in cats is lymphoma, followed by mammary cancer and oral cancer, such as squamous cell carcinoma. Most cats are between 10 – 15 years of age at diagnosis.


Dogs can develop a variety of different cancers as they age, and certain breeds, such as Golden Retrievers, Boxers, Bernese Mountain Dogs, and Greyhounds, are genetically predisposed to the development of certain cancers. Lymphoma, along with abdominal and skin cancers, are the most common cancers found in dogs. However, we also see bone, mouth, and urinary tract cancers with moderate frequency as well.



Cancer can only be definitively diagnosed based on the identification of cells from a direct sample. Cell samples are generally obtained by either a needle stick or a small biopsy. In addition to sampling, bloodwork, urine tests, and imaging, such as X-rays, ultrasound, and CT/MRI, may be helpful in obtaining additional information.


Treatment for cancer depends entirely on where the cancer is located, whether or not it has spread to other parts of the body, how amenable it is to surgical removal, and whether or not the cell type involved responds well to chemotherapy. Treatment generally involves surgery, radiation therapy, and/or chemotherapy. Certain tumors, such as melanoma, can also be treated with vaccination. Pain management is a critical part of any treatment protocol.


There is no single cause for cancer, so it is nearly impossible to prevent. However, certain reproductive tumors, such as testicular cancer, ovarian cancer, uterine cancer, and potentially mammary cancer can be prevented through spaying and neutering. Feline leukemia can also be prevented through vaccination.