Mammary Carcinoma in Cats

A mammary (breast) tumor is a common tumor in the cat. The first sign of this type of cancer may be a fluid-filled or firm lump associated with the mammary gland or discharge originating from the nipple. These masses do not tend to be painful but can be associated with increased grooming behavior if discharge is present.

The majority of mammary tumors in cats are malignant and very likely to metastasize (spread to other locations) early in the course of the disease. The most common locations for tumor metastasis are the lymph nodes in the area and the lungs. A needle aspiration of the affected tissue may be adequate to diagnose mammary carcinoma; however, biopsy may be necessary in some instances. Prior to any biopsy or treatment, palpation of those local lymph nodes and chest X-rays are recommended to look for evidence of metastasis. Blood work to evaluate organ function is also recommended.

Designing a treatment strategy for a patient with a metastatic (cancerous) tumor requires attention to two aspects of the disease. The first aspect is to achieve control of the primary tumor, and the second is to improve the patient’s lifespan. With this in mind, the treatment for mammary cancer typically involves surgery to remove the affected chain of mammary glands followed by injectable chemotherapy to treat any cancerous cells that have already metastasized.

Many people are nervous about the side effects that may occur with chemotherapy; however, protocols have been developed to be effective while minimizing side effects to your pet. Therefore, most feline patients tolerate chemotherapy exceptionally well and do not have any side effects. The protocols often utilize doses that are lower than those used in human medicine, allowing cats to maintain an excellent quality of life throughout treatment

The cost of treatment is based on the type of surgery and/or chemotherapy drugs. During your evaluation, the oncologist will have an extensive discussion with you about your pet and what treatments will be most appropriate. You will then be provided with the estimated costs involved with diagnosis and treatment.

For more information on this subject, speak to the veterinarian who is treating your pet.