Most men with breast cancer present with a mass in the breast, the evaluation of which should include a tissue diagnosis. If the presence of invasive cancer is established, adequate local therapy includes total removal of the breast. Most tumors are hormone-receptor positive. In high-risk patients, the use of endocrine adjuvant therapy and/or combined endocrine and chemotherapy should be considered. Patients with estrogen-receptor (ER)-negative disease should be offered chemotherapy. In patients with metastatic disease and ER-positive tumors, initial treatment should be endocrine therapy; systemic chemotherapy should be used in patients who are either hormone-receptor negative or resistant to available endocrine therapies.