​Breast cancer develops when abnormal cells grow uncontrollably in the breast tissue, forming a tumor that may spread to other parts of the body if left untreated. It is one of the most common cancers among women, although men can also develop it. Early signs may include a breast lump, changes in the size or shape of the breast, nipple discharge, skin dimpling, or nipple inversion. Early detection through regular breast self-examinations, clinical examinations, and mammography greatly improves treatment outcomes. Depending on the stage of the disease, treatment may include breast-conserving surgery, mastectomy, sentinel lymph node biopsy, chemotherapy, radiation therapy, hormone therapy, targeted therapy, or immunotherapy.