Mammary Cancer

 

Overview on Mammary Gland Cancers:

About one-half of mammary gland cancers are malignant, and the other half are benign. Spaying dogs at an early age reduces the risk of this type of cancer to 0.5% if done before the first heat and to 8.0% if done before the second heat, compared to intact bitches.

Benign mammary tumors typically manifest as small, slow-growing masses. In contrast, malignant tumors tend to grow faster, appear as single or multiple, also can be ulcerated masses. Metastasis indicates aggressive tumors and can spread to any organs, particularly the lungs, adjacent mammary glands, and lymph nodes.

Definitive diagnosis is typically achieved through histopathology. Veterinarians often request chest and abdominal X-rays for further assessment before initiating treatment.

Treatment for this cancer can involve various surgical methods depending on factors such as size, location, single or multiple masses, and the number of mammary glands and lymph nodes involved. Options may include simple lumpectomy, removal of one or two mammary glands, excision of all mammary glands in one or both sides (known as a chain mastectomy), or a radical mastectomy involving the removal of all breasts, the skin covering them, and the associated lymph nodes simultaneously.

The common classes of mammary tumors that might be found on a biopsy.

Fibroadenoma:
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.
Adenocarcinoma:
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.
Inflammatory Carcinoma:
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.