Breast Cancer in Cats

Picture of a spotted cat

Cat breast cancer is one of the most common types of cancers that affect our feline companions. As much as ninety percent of all malignant tumors found in cats are breast tumors, and according to some sources, when it comes to its prevalence, it is surpassed only by skin cancers and lymphoid cancers.

Breast cancer in cats is not breed specific. However, Japanese breeds along with Siamese cats seem to be affected by the illness more often than other types of cats. Cats that have been spayed are less exposed to the risks of developing this type of neoplasia during their lifetime.

In this article, we’ll look at several facts about cat breast cancer, its clinical signs, whether it can be treated, and whether it can be prevented.

What about Male Cats?

Although it is extremely uncommon, breast cancer can also affect male cats, just like breast cancer in humans can also affect males. That is why we recommend that you take your male cat to the vet if you feel any lump on his belly or chest or notice a strange-looking sore in the same area.

Symptoms of Breast Cancer in Cats

Unfortunately, in most cases, by the time the cat is finally brought in for examination, the neoplasia is in a somewhat advanced stage. Tumors are typically nodular and firm and could adhere to the overlying skin. Sometimes, if they are quite large and if they put a lot of strain on the skin, they might ulcerate — this can happen in about one quarter of all of the cats that are affected by breast cancer.

The nipples may be involved, as well, and they can become swollen or take on a reddish tint. In some cases, they might ooze clear or slightly yellow fluid.


The diagnosis can involve several types of tests. Naturally, most mammary tumors are apparent, so they can be seen with the naked eye, but that doesn’t mean that the type of cancer or its malignancy can also be established visually.

The physical examination has the purpose of determining the site, the number, and the size of the primary tumors. Serum and blood chemistry profiles, along with urinalyses are used to evaluate the cat’s health status, whereas abdominal ultrasounds and/or X-rays can be utilized to find out whether the tumors have spread to other organs. In most cases, mammary tumors that affect the abdominal area spread to abdominal organs whereas those that are thoracic can, unfortunately, spread to the lungs.

85% of the mammary masses found in cats are of a malignant nature, so the veterinarian might recommend special diagnosis methods such as biopsy or cytology.

Treatment Options

There are three main types of treatment when it comes to cat breast cancer. One is surgery, the second is chemotherapy, and then there is the option of radiation therapy. In our feline friends, there isn’t any evidence that suggests that cats’ mammary cancer life expectancy increases thanks to radiation therapy, and that is why it is not routinely utilized for the treatment of the disease. It does offer good results in dogs, though.

Chemotherapy can be used in cats and there are two drugs that seem to be effective – cyclophosphamide and doxorubicin. However, to date, more studies have to be performed to assess the combination and doses of drugs that can increase the cat’s survival.

Surgery is by far the most common treatment used nowadays, and that’s because the goal is to remove the tumor, especially in cases where it has not spread to other organs but it is malignant. Even if the cat has the tumor removed, there could be cancer cells that have traveled to other organs, so although the patient could be in remission for a period, the cancer could come back.

While in dogs, surgery usually involves the removal of just one mammary gland or in any case, those that have been affected, in cats it is recommended that bilateral mastectomy is performed. To increase the efficiency of the treatment, surgery can also be combined with chemotherapy following the operation.

We recommend getting pet insurance because the cat breast cancer surgery cost can be extremely high. There are cases where people have paid more than $7,000 on the operation and subsequent medication and treatment.


Cats with tumors that are smaller than 0.8 inches have a high chance of surviving for more than three years. Those that have neoplasms that measure between 0.8 inches and 1.2 inches have an average life expectancy of approximately two years. Unfortunately, those with tumors that are bigger than 1.2 inches have an average survival time of four to six months.

Because mammary cancer can affect any cat regardless of age, gender, or breed, we would suggest getting your pet to the vet as soon as you notice any lump whatsoever. It’s always better to discover the cancer while it is in an incipient phase – it’s easier to treat, your pet’s health status hasn’t been affected too much, and the cat has a good chance of living for many years.

Can You Do Anything to Prevent It?

The truth about cancer is that it can be caused by a myriad of factors, and many of them are still unknown. From the genetic history of the animal to actual oncogenic viruses – there are many things that can cause cancers of any kind. It can be caused by hormonal drugs or changes in hormonal levels, too, but it can also be caused by some types of pet food, especially highly processed varieties.

You can do three things to try to limit your cat’s risk of developing a mammary tumor in the future. One of them is to inspect her regularly and make sure that you pet her and gently feel every inch of every body surface. This will help you discover any type of mass before it’s too late to treat. The second measure you can take consists of feeding your cat some food that’s as natural as possible and that doesn’t contain any preservatives or artificial flavors or colors.

Finally, the most effective method of preventing mammary and genital cancer in both cats and dogs is to have your pet spayed before he or she enters the first heat cycle. Even if you do not manage to do that, you can still prevent cancer by spaying your pet before they reach the age of 12 months.



Leave a Reply

Your email address will not be published. Required fields are marked *

Table of Contents