Breast cancer is a condition in which abnormal cell growth occurs in the breast. Although men may get breast cancer, the overwhelming majority of cases occur in women. American women get breast cancer more than any other type of cancer (except for skin cancer). Breast cancer can be invasive (moves into the surrounding tissue) or non-invasive (stays in the ducts or lobes). Most cases of breast cancer are invasive. A few of the treatment options for those with breast cancer include surgery, radiation therapy, and chemotherapy.