Breast cancer is unfortunately prevalent not only among humans, but also in our feline friends. Just like with people, mammary cancer is very aggressive in cats, and they have the best chance of survival if caught early.
“Eighty-five percent of mammary tumors found in cats are malignant, and more that 80 percent will eventually spread to other locations in the body,such as the lymph nodes, lungs, bone, and internal organs,” said Dr. Jacqueline Bloch, medical oncology resident at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.
It is found that Siamese and domestic short hair cats are more at risk for mammary tumors. “Siamese are especially prone to developing them at a relatively young age,” Bloch said. “The average age is 10 years in other cats.”
However, it is a risk for any cat to develop a mammary tumor, and like with other cancers, it is important to get a proper diagnosis.
“Mammary tumors in cats are best diagnosed by a biopsy; this helps us to give prognostic information to the owners as well as diagnosis,” Bloch said. “Sometimes we can obtain diagnosis by a relatively non-invasive needle biopsy.”
Similar to dealing with other tumors, the best treatment option is to surgically remove them. Because the feline form of mammary cancer is so aggressive, veterinarians generally recommend a staged bilateral mastectomy, or the removal of all the mammary glands in a staged manner.
“Cats have four pairs of mammary glands, and they are intimately associated and share lymphatic drainage, which is why we recommend removing them all,” Bloch said. “There should be one surgery on one side to remove the glands, then after waiting for two-four weeks to let them heal, we surgically remove the other side.”
Before executing such an extreme surgery, Bloch explains that they will perform what is called staging tests to look for evidence of cancer that has spread to other parts of the body.
“This normally means an abdominal ultrasound to look for spread to regional lymph nodes or liver and spleen, and chest radio-graphs to look for evidence of spread to the lungs,” Bloch said. “If these show no evidence of disease, we recommend going forward with the surgery.”
Depending on the case, chemotherapy may be recommend following surgery if the tumor is very aggressive and the patient proves to be a good candidate.
Although it is impossible to completely prevent mammary cancer, the early spaying of cats is very protective against developing these tumors. “Spaying a kitten before six months of age can ultimately reduce the risk of developing breast cancer by 91 percent.” Bloch said.
Like with humans, cats have the best chance of survival if the mammary tumors are discovered early. Regularly examining your cat by rubbing their belly and gently squeezing the mammary glands, as well as taking them in for regular check-ups at the veterinarian, is effective for early detection and catching the cancer in time, for the best possible outcome.
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