Signs and symptoms of breast cancer include a new lump in the breast area, nipple retraction, and swelling and tenderness in the breast and nipple, according to the American Cancer Society. Breast cancer that spreads to the lymph nodes may also cause swelling under the arms and around the collarbone.
Breast cancer is a malignant tumor that develops from an abnormal growth of cells in the breast, explains the American Cancer Society. Due to its malicious nature, the cancer may invade surrounding tissue and metastasize to other areas of the body. Although the disease affects women almost exclusively, it occurs in men in rare cases.
Doctors have not identified the exact cause of breast cancer as of 2015, though some risk factors may contribute to its development, states WebMD. These include a family history of breast cancer, a previous personal history of benign lumps in the breast, advancing age, long-term exposure to the hormone estrogen, and heavy doses of radiation therapy.
Doctors determine the type of breast cancer treatment by analyzing factors such as the tumor size, the patient's age, her personal preferences, her menstrual status and how far the disease has spread in the lymph nodes, explains WebMD. For cancer contained in the breast area and surrounding tissues, treatments include mastectomy, lumpectomy and radiation therapy. For cancer that has metastasized, systemic treatments include chemotherapy, hormone therapy and biological therapy.