Breast cancer is cancer that forms in the cells of the breasts. After skin cancer, breast cancer is the most common cancer diagnosed in women in the United States. Breast cancer can occur in both men and women, but it's far more common in women. Breast cancer can occur in women and rarely in men.Symptoms of breast cancer include a lump in the breast, bloody discharge from the nipple and changes in the shape or texture of the nipple or breast.Its treatment depends on the stage of cancer. It may consist of chemotherapy, radiation, hormone therapy and surgery. New lump in the breast or underarm (armpit) Thickening or swelling of part of the breast. Irritation or dimpling of breast skin. Redness, scaliness, pitting or thickening of the skin or nipple. No actual tumor is found in the breast. The tumor is smaller than the approximate size of a peanut (2 centimeters or smaller). Similar to stage 0, breast cancer at this stage is very treatable and survivable. When breast cancer is detected early, and is in the localized stage, the 5-year relative survival rate is 100%.