Mammary Tumors in Cats

Mammary tumors are one of the most common tumors found in cats. There may be some sort of genetic link as two breeds - the Domestic Shorthair and Siamese - seem to be diagnosed with them more frequently.

Intact or unspayed females cats seem to be most at risk. However, mammary tumors can be found in both spayed cats or even, rarely, male cats. Age also seems to play a role in the incidence of mammary tumors. Older cats (average age 11) are much more likely to develop them.

Causes of Mammary Tumors in Cats

The specific cause of mammary tumors in cats is still unknown. However, hormones likely play a significant role in their development. Sadly, approximately 85-90% of mammary tumors found in cats are malignant, grow fast, and are classified as “adenocarcinomas” or “cancer of a gland.”

Symptoms of Mammary Tumors in Cats

The mammary glands close to or near the chest/ribcage are most likely to be affected. Mammary tumors often start out feeling like a small, firm nodule, almost like a BB pellet. There can certainly be more than one nodule or mass per gland.

In advanced stages, the masses become larger and may even become an infected, open, draining sore. If malignant, one of the most common areas of the body that they spread to are the lungs.

How are mammary tumors diagnosed?

Mammary tumors are usually found just by feeling along the mammary chains either by a very astute cat owner or a veterinarian during a routine physical exam. The next step is usually to perform some screening blood work (chemistry and CBC or “Complete Blood Count”) and urinalysis to evaluate the cat’s overall health. X-rays and ultrasound are also excellent diagnostic tools and are recommended to check for any additional tumors and/or other abnormalities.

Treatment Options for Cats with Mammary Cancer

Surgery is the most common form of treatment for mammary cancer in cats. A “radical mastectomy” or removal of all mammary glands on one side and some lymph nodes is usually recommended as there is a high recurrence of this type of cancer.

Your vet will send off part or all of the mass(es) for a pathologist to evaluate and make recommendations. As a general rule with this type of cancer, the best prognosis is directly related to early detection and treatment.

Although not widely used, chemotherapy after surgical removal can also be helpful in the treatment or at the recurrence of mammary cancer in cats. There are no home remedies for mammary tumors in cats.

How to Prevent Mammary Cancer in Cats

Spaying at a young age (6-12 months) will decrease the risk of breast cancer in a cat.

One of the best things you can do for your cat at home is to frequently feel along and under both sides of the mammary chains (there should be four nipples on each side.) Familiarize yourself with how the tissues feel, and should you come across anything new or different, contact your vet right away.

When to Contact a Vet

If you find any sort of mass, new or unusual tissue, or even discharge from your cat’s nipples, it’s important to contact your vet right away, as early detection is the key to success in the surgical removal or treatment of mammary tumors or any other type of mass for that matter. Your cat will no doubt love those extra belly rubs...usually!...

Read more:

What You Need to Know About Spaying or Neutering your Cat

Cancer (Neoplasia) in Cats

Need to speak with a veterinarian regarding your cat’s mammary tumor or another condition?

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