Symptoms & Treatment of Dog Breast Tumors: What You Nee
Canine breast tumors are a common type of neoplastic disease in older dogs, with a significantly higher incidence in female dogs compared to male dogs. Breast tumors can be classified as either benign or malignant, with approximately 30% to 50% of canine breast tumors being malignant.
Most breast tumors in dogs occur in middleaged to senior pets, with young dogs rarely being affected. The incidence of breast tumors increases notably after the age of 5, with the highest prevalence occurring between the ages of 8 to 12. Breeds like the Lion Dog, Pomeranian, German Shepherd, and Samoyed have the highest rates of breast tumors.
Dogs with breast tumors may exhibit localized swelling in the breast area and surrounding subcutaneous tissue. These swellings are typically firm, painless, and without heat. Initially, clinical symptoms may be vague. However, as the tumor progresses, it may become damaged and溃破, leading to infection, abscesses, and systemic symptoms such as weight loss, anemia, and decreased appetite. Some dogs may also experience symptoms like coughing.
Breast tumors refer to the presence of one or more nodules in the breast tissue. Dogs have five pairs of mammary glands, and all of these can develop benign or malignant tumors. The fourth and fifth pairs, which contain the most mammary tissue, are more prone to breast tumors. The incidence rate is around 70%. Benign tumors are usually small, mobile, and have a firm texture upon palpation. Malignant tumors, on the other hand, grow rapidly, have unclear edges, and may adhere to the skin or subcutaneous tissue, along with possible ulceration or inflammation.
Benign breast tumors typically appear as small, welldefined nodules, often oval in shape, with clear boundaries and a firm texture. The tumor is somewhat hard, encapsulated, and has minimal bleeding on incision. Malignant breast tumors are pale red, with an incomplete capsule, and have a grayishwhite, friable texture with slight bleeding. Microscopic examination shows that benign tumor cells are welldifferentiated, resembling surrounding tissue cells, but with larger cell shapes. Malignant tumor cells are poorly differentiated and differ in structure from surrounding tissue cells.
The fundamental treatment for canine breast tumors is surgical removal of the tumor tissue. Medications can only serve as supportive therapy and aid in postoperative recovery. There are various surgical methods for removing breast tumors, with the most common being unilateral or bilateral mastectomy (removal of one or both breasts and lymph nodes), and local mastectomy (removal of multiple mammary glands, connective tissue, and lymph nodes).
The primary goal of surgery is to remove the affected tissue to prevent further growth and spread of the tumor. It is also important to consider that malignant tumors may spread to local lymph nodes via lymphocytes. While a more extensive resection of focal lesions can reduce the likelihood of new tumors, it does not prevent potential metastasis.
Factors that influence the prognosis after surgery include tumor size, extent of lymph node involvement, presence of distant metastasis, histological type, grade of malignancy, nuclear differentiation, the reaction of lymphocytes near the tumor, the degree of invasion, vascular growth, and hormone receptor status. Small dogs tend to have longer lifespans but a higher likelihood of benign tumors, while large dogs have shorter lifespans and a lower likelihood of benign tumors. Additionally, tumor size is a significant factor in prognosis; dogs with invasive tumors that are less than 3cm in diameter have a better prognosis than those with tumors equal to or larger than 3cm in diameter.
