Breast cancer in cats is more commonly known as mammary tumors and/or mammary cancer. Cats can get either benign or malignant forms of mammary cancer, though cats overwhelmingly suffer from malignant mammary cancer. In this article we’ll discuss more about mammary cancers in cats, your cat’s potential risk, and what can be done for care.
What Is Mammary Cancer in Cats?
First, we should explain where mammary tissue is on your cat. When your cat rolls over onto their back, and you see their “belly”, you’ll notice two lines of nipples that run from each armpit towards the groin area. These are the two mammary chains in cats, and they consist of the underlying mammary tissue and associated nipples. Cats can develop growth abnormalities, infections, and different types of cancers anywhere along these mammary chains.
Sometimes a cat will develop a single mammary tumor; other times large portions of one or both mammary chains will be affected with multiple tumors. The tumors or cancer may be benign or malignant. Unfortunately, cats often develop malignant cancers with mammary carcinoma being the most common.
What Are the Signs of Feline Mammary Cancer?
You may notice a small lump near one or multiple nipples on your cat at first. The tumors may be as small as a BB. Other times you may not notice the tumor(s) until they are much larger, especially if your cat hates having their belly touched. These tumors may or may not have any hair loss associated with them, and oftentimes are the same color as your cat’s skin if not just slightly pink in color.
As the tumors grow and multiply, you may notice more than growth separately, or potentially multiple that all seem to now be growing into one another and/or connecting. These tumors are often slightly soft to firm when you feel them, and your cat may be sensitive to palpation of the tumors. These tumors may rupture or burst open, causing significant bloody discharge.
Your cat may act completely normal at first. Because of this, you may not notice anything wrong. If your cat has malignant cancer, over time you may notice weight loss, a decreased appetite, vomiting, diarrhea, abnormal vocalizing, and decreased grooming. Some cats will also develop difficulty breathing if the cancer spreads to their lungs and/or makes fluids within the chest or abdominal cavities.
What Are the Causes of Mammary Cancer in Cats?
This is the million-dollar question with not only mammary cancer, but many different types of cancers. What we do know is that female reproductive hormones (estrogen and progesterone) significantly increase the risk of your cat developing mammary cancer. What exact role these hormones play in cancer development is still being studied.
But it’s well known that cats who are left intact, or have never had an ovariohysterectomy (spayed), may have up to a seven-fold increase in developing mammary tumors as compared to cats who have been spayed. Some studies even suggest that spaying a cat prior to 6 months of age will also decrease their chances of developing mammary cancer as compared to cats spayed between 7 and 12 months of age. It’s also well documented that female cats overwhelmingly suffer from mammary cancer more than male cats.
The majority of mammary cancers are also diagnosed in middle-aged to older cats. But as with most cancers, it’s important to remember that any cat can develop cancer, even at a young age. Because there are so many unanswered questions about cancer, if you feel any type of lump on your cat, it’s best to get it evaluated by a veterinarian.
Diagnosing Mammary Cancer In Your Cat
First, it’s imperative to know that your cat will need some type of tissue sampling for a diagnosis. Your veterinarian will not be able to just feel the tumor and know whether or not it is malignant or benign.
There are two recommended diagnostic tests that your veterinarian may recommend. One is a fine needle aspirate. This method does not require any sedation (unless your cat is typically very spicy at the vet), is quick and simple. It involves your veterinarian agitating or aspirating the tumor(s) with a needle and syringe. By doing this, cells are sucked up into the needle. These cells are then sprayed and spread onto a microscope slide and sent into a laboratory for a pathologist to evaluate under the microscope.
The other way to diagnose mammary cancer is with a tissue sample, or biopsy. This often includes heavy sedation or sometimes anesthesia. Your veterinarian will obtain multiple small pieces of tissue that are typically placed in formalin and then sent to a lab. Depending on the biopsy site, your veterinarian may have to place a few sutures to close the tissue and allow it to heal.
If your cat is diagnosed with mammary cancer, chest radiographs and an abdominal ultrasound may also be recommended to see if there has been obvious metastasis, or spread of cancer. Full blood work is often done as well to monitor red blood cell, white blood cell, and platelet counts as well as monitoring blood work values of other organs.
How Do I Care for a Cat With Mammary Cancer?
It’s always best to discuss and come up with a care plan with your veterinarian. Depending on your cat’s specific case, you may be referred to a Board Certified Veterinary Surgeon, Oncologist, or even Internal Medicine specialist. Your veterinary team can best discuss options with you depending on your specific cat.
Surgery is typically recommended to remove either a single tumor, or having a radical chain mastectomy performed. This is when all of the mammary tissue along a side of the body is removed. Some cats will even have to have both sides of the mammary tissue removed. This is a significant surgery that carries significant healing time, pain control, and aftercare. However, it may give your cat their best prognosis.
There is nothing holistically that can be done at home to help treat and/or prevent mammary cancers. Because scientists are still studying what causes these cancers in the first place, no one treatment or combination of treatments is foolproof. As mentioned above, a care plan, whether hospice/comfort care or surgery with chemotherapy, should always be discussed with your veterinarian.
Frequently Asked Questions (FAQ)
Can I Prevent Mammary Cancer in My Cat?
The most important thing you can do to greatly reduce your cat’s risk of mammary cancer is to have your cat spayed prior to their first heat cycle. Not only are you greatly reducing their cancer risk, but you are also helping control the cat overpopulation issue and decreasing your cat’s chance of developing a pyometra.
What If There’s Only a Small Mass?
Get diagnostics done by your veterinarian! Mammary cancers, if malignant, can be extremely fast growing. If you only feel one small lump, your veterinarian may be able to surgically remove it before it has a chance to metastasize or grow so large that a radical mastectomy has to be performed.
Conclusion
Breast cancer is known as mammary cancer in cats. It’s overwhelmingly more common in female cats versus male cats, most frequently occurring in females who have never been spayed. While we don’t know the exact cause of mammary cancer, there is some evidence suggesting that the female reproductive hormones play a role. Cats can get malignant or benign mammary cancers, but sadly tend to develop malignant carcinomas most frequently. A definitive diagnosis with either cytology or histopathology is recommended prior to coming up with a treatment plan. Your veterinarian may recommend surgery and chemotherapy. Prognosis is completely dependent on the type of cancer, evidence of metastasis, and overall health of your cat at the time of diagnosis.
Featured Image Credit: MaxxPhotoStock, Shutterstock
