October was declared as Breast Cancer Awareness Month by the American Cancer Society in the 1980s. Nearly 250,000 women are diagnosed with breast cancer every year in the United States. While there is still a long way to go in curing this terrible illness in humans, thanks to the ACS, we are much more aware of this cancer, leading to increased screening and earlier diagnoses in women.
However, did you know that your pets are also at risk for breast cancer?
Breast cancer is one of the most common cancers in our pets, and can be a devastating diagnosis. Just like human women, breast cancer can be an aggressive cancer in our furry family members, leading to severe illness, pain and death if it spreads to other organs.
While any pet can get breast cancer, older female pets are most at risk. Cats are typically diagnosed after age 10. Dogs tend to be diagnosed after age six. Pets that are unspayed, or were spayed later in life, had a history of a previous litter of puppies or kittens, or have a family history of cancer are more at risk. Any breed of dog or cat can get breast cancer; however, Siamese cats are more at risk than other cat breeds.
The first sign of breast cancer is a lump on or near a nipple. These can be extremely small at onset; they tend to be firm. Over 50 percent of breast lumps in dogs are malignant, and 95-plus percent of breast lumps in cats are malignant.
As the cancer progresses, the lumps can become larger, spread to additional nipples, and you may notice discharge, pain, bruising or ulceration. If the cancer spreads to other parts of the body, dogs can become quite sick, with lethargy, fever and decreased appetite. In cats, the cancer tends to travel to the lungs, leading to coughing.
While extremely rare, male dogs and cats can develop breast cancer. Research into this is limited, but results show that male cats usually have an extremely poor prognosis, but male dogs have a more favorable prognosis.
Please schedule an appointment with your veterinarian for any new breast lumps. Your veterinarian will go over the appropriate treatment options for you and your pet. They may wish to do diagnostics such as X-rays, ultrasound or bloodwork to help them determine if the cancer has spread. For uncomplicated early cases, surgery is generally recommended to remove the breast tissue (mastectomy). For complex cases, or if the cancer has spread, your veterinarian can discuss chemotherapy and radiation options or palliative care. They may wish to refer you to a veterinary oncologist if they believe it is indicated for your pet.
The most important thing that you can do to prevent breast cancer in female dogs and cats is having them spayed. Up to one in four dogs will develop breast cancer if they are left intact. Dogs spayed before the second or third heat cycle see vast decreases in risk. Cats spayed before their first heat cycle have a nearly non-existent risk of developing breast cancer.
As a personal aside, I found a small, BB gun pellet-sized lump on one of my personal beloved cats, Miss Lucille McGuillicuddy’s left nipple in early 2023. She was diagnosed with an aggressive breast cancer (mammary adenocarcinoma) two weeks later. I was devastated. Very few cats live even a year after diagnosis. After three radical mastectomy procedures, Lucy is defying all odds as a breast cancer survivor. Because her cancer was caught early, she is now feeling great and can look forward to sneaking cheese off the counter for years to come.
As we see the pink ribbons this month, please take care to do a comprehensive breast exam on your female pets. Remember that your pet has eight-plus nipples! Any new lumps or bumps should be brought to the immediate attention of your veterinarian. With your help, breast cancer does not have to be a death sentence.
[Dr. Cecelia Harmon DVM is an associate veterinarian at Drummond Animal Hospital in New Bethlehem.]
