Most breast cancers in men are ductal carcinomas. Ductal means the cancer started in the milk pipes of the breast, called ducts. These cancers are usually invasive because they start inside the duct and then break through the wall of the duct, growing into the normal surrounding breast tissue.
Treatment for advanced breast cancer can often shrink or slow the growth of the cancer (sometimes for many years), but after a time it may stop working. Further treatment at this point depends on several factors, including previous treatments, where the cancer is located, and a man's age, general health, and desire to continue getting treatment.
The main treatment for breast cancer in men is surgery to remove the tumor. This is usually a mastectomy. Lumpectomy (also called breast conserving surgery) is rarely used because of the small size of a male breast. Some men may have radiation therapy following surgery, depending upon the stage of the breast cancer.