Breast Cancer in Dogs
What is Breast Cancer in Dogs
Breast cancer, also known as mammary gland tumors and mammary cancer, is the most common cancer in female dogs, accounting for roughly 50% of all of the tumors in bitches. Breast cancer is uncommon in male dogs, because their mammary glands exist in a very primitive state. “Tumors” are swellings, masses or growths of new tissue that are often referred to as “cancers” or “neoplasms.” They can be malignant or benign. “Malignant” tumors are those that tend to progressively worsen over time and, without treatment (and often even with treatment) almost always eventually result in death. They are invasive, grow uncontrollably and spread (metastasize) to other areas of the body. “Benign” tumors are those that are not malignant – in other words, they typically do not invade nearby tissue, grow uncontrollably or spread widely. The term “breast cancer” encompasses both malignant and benign tumors that originate from mammary gland tissue.
Mammary gland tumors always start with abnormal growth of mammary tissue. They are classified by the type of mammary tissue involved. Roughly 30% to 50% of breast tumors in dogs are malignant. Most (but not all) of these tend to be highly aggressive and invasive, spreading to the lungs, to nearby lymph nodes and possibly to other places, such as the liver and kidneys.Malignant mammary tumors include:Benign mammary tumors include:What causes breast cancer to develop
Dogs with breast cancer often don’t seem to know that they have it, especially during the early stages. Certain types of breast cancer, such as inflammatory carcinoma, are very aggressive and can cause the affected mammary glands to ooze, abscess and become extremely painful. But again, in most cases, the affected dogs seem to be oblivious to their condition.Many times, breast cancer is found during a routine physical examination when a dog’s owner had no
Most veterinarians will take a thorough history from any dog’s owner about its overall health, and also perform a complete nose-to-tail physical examination, regardless of why the animal has been brought to the clinic. Sometimes, breast tumors are detected incidentally during a routine annual physical examination, while other times the owner brings her pet to the doctor specifically because she has felt something lumpy in one or more of her dog’s mammary glands. In either
The primary goal of treating a dog with breast cancer is to surgically and completely remove all cancerous masses along its mammary chain. If the tumors are inoperable or have already spread, or if the owner is unable or unwilling to proceed with the surgery either financially or otherwise, the therapeutic goal becomes to manage the disease so as to improve or at least maintain the dog’s quality of life for as long as possible.The