Mammary Gland Cancers - Dogs
About one-half of mammary gland cancers are malignant, and half are benign. Spaying dogs at early age decreases the risk of having this type of cancer to 0.5% if dogs spayed before the first heat, second to 8.0% if Spayed before second heat compared to intact bitch.
Benign Mammary tumors are usually noticed as small slow-growing masses. Malignant tumors are usually growing faster, single or multiple masses, sometimes ulcerated. Metastasis is a sign of the aggressive tumors and can spread to any organs particularly lung, the adjacent mammary glands, and lymph nodes.
The definite diagnosis can be achieved by histopathology. However veterinarians always request chest & abdominal X-ray for further assessment and before starting any treatment.
This cancer can be surgically removed by different methods depends on size, location, single or multiple, number of mammary gland & lymph nodes invaded. For example, vets can choose between simple lumpectomy, removing one or two mammary glands, all chain mammary glands in one or both sides. A radical mastectomy means all the breasts, the skin covering them, and the lymph nodes are all removed at one time.
The common classes of mammary tumors that might be found on a biopsy.
A benign glandular tumor usually no treatment is necessary.
Mixed Mammary Tumor:
What is mixed is the type of cell that makes up the tumor: the epithelial cells that line the glandular tissue and the mesenchymal cells that make up the non-glandular portion.
Adenocarcinomas can be tubular or papillary, depending on the gland cells the tumor arises from. Adenocarcinomas behave malignantly but how aggressively malignant they are depends not on whether they are tubular or papillary, but on other cellular characteristics described by the pathologist (such as how quickly the cells appear to be dividing and how closely they resemble normal gland cells). When the oncologists reads the description they will be able to determine how aggressively to combat the tumor.
A highly malignant tumor that generates tremendous inflammation locally with ulceration, pus, and discomfort. This type of tumor tends to spread early in its course and is difficult to treat.
Approximately 50% of malignant mammary tumors will have already spread by the time of surgery. The other 50% are confined locally and surgery is curative. If you notice lumps on pet abdomen, contact your veterinarian or call our pet clinic in Newmarket Aurora area at 905-898-1010