As you may be aware, October isNational Breast Cancer Awareness Month (NBCAM). The NBCAM organization is a partnership of medical associations, public service organizations, and governmental agencies working together to promote awareness of breast cancer issues, and we commend them for their excellent work.
But while we honor our mothers, sisters, and daughters by raising the public consciousness about breast cancer, let’s honor our pets as well by keeping in mind that they too can develop breast cancer.
A preventable problem
Usually referred to as “mammary cancer” in pets, it can affect both dogs and cats and is sometimes fatal, although it can often be cured. Even more importantly, however, is that most cases can be easily prevented.
“Mammary cancer is pretty rare in the United States,” said Karen Oberthaler, VMD, ACVIM, a board-certified veterinary oncologist at NYC Veterinary Specialists in New York. Why? You may be wondering. “Most mammary cancers in dogs and cats can be prevented by spaying,” Oberthaler said, and most American pet owners do choose to spay or neuter their pets. (Surprisingly, the spay/neuter rates in Europe are much lower and, as a result, their pets suffer much higher rates of mammary cancer.)
In fact, in the case of dogs, Oberthaler said that 94% of mammary cancers could be prevented by spaying before the animal has had its first heat. According to the veterinary textbook “Canine Oncology: A Comprehensive Guide for Compassionate Care” by veterinary oncologists G.K. Ogilvie and A.S. Moore, “intact [i.e. unspayed] females have a sevenfold increased risk of developing mammary cancer as compared to spayed females.”
The incidence of mammary cancer in cats is lower, but with cats as with dogs, spaying early is the key to prevention.
How serious is it?
Any form of cancer is a serious matter, and mammary cancer is no exception. Oberthaler cited the so-called “50/50” rule: 50% of tumors in dogs are cancerous; of those, 50% can be cured by proper treatment.
In cats, 90% of mammary tumors are cancerous and the disease is more likely to metastasize (spread to distant sites in the body). The disease therefore tends to have a less favorable outcome in cats than in dogs, though cure is possible.
What are the treatments?
Surgery is the treatment of choice for all mammary tumors in both cats and dogs. In dogs, surgery usually consists of removal of the tumor; the mammary glands themselves are spared. The surgery in cats tends to be more invasive, as Oberthaler explained: “In cats, we usually perform what’s called a unilateral radical mastectomy, which means that we remove one of the two chains of the cat’s mammary glands. This is because in cats, metastasis is more likely.”
Chemotherapy is sometimes used in dogs with higher-grade — more malignant — tumors. In cats, chemotherapy is always recommended because of the greater risk of spread of the cancer from the primary site.
The key: early diagnosis
As in so many different cancers – both human and animal – early diagnosis greatly increases the likelihood of cure. Oberthaler recommends periodically examining your pet: “It’s as simple as a good belly rub,” she said. “Feel your pet’s belly carefully every month or so, examining each of the teats. But remember that the mammary glands extend high up the animal’s body, so feel all the way up the rib cage.”
So, the message? First: spay your female pets and do so when they’re young. Second: remember the belly rub!