Breast cancer is a rapid, uncontrolled growth of abnormal cells in one or both breasts. It is the most common type of cancer in women, but it is highly curable when caught early.

While the number of women who have breast cancer increases with age, the disease can affect women in their 40s and, rarely, women in their 30s. Having a family history of breast cancer is an important risk factor, but most women who develop breast cancer do not have any known risk factors other than their age. Although rare, breast cancer can occur in men.

The most common symptom of breast cancer is a lump or thickening in the breast. Other symptoms include changes in the skin of the breast, spontaneous nipple discharge or bleeding, and scaling or crusting of the nipple.

Treatment for breast cancer depends on the stage of the breast cancer, whether nearby lymph nodes contain cancer cells, and how the cancer cells look under the microscope. Treatment usually includes surgery to remove the cancer. Chemotherapy and radiation may also be used to treat breast cancer.