The extent to which current treatment for breast cancer succeeds in prolonging life remains open to question. Despite evidence that mastectomy, radiation following lumpectomy, axillary node dissection, or intensive follow-up surveillance have little impact on survival, these practices are adhered to tenaciously. The widespread acceptance of many ideas and interventions is perilously disconnected from their actual merit. The imperative for doctors to do something sometimes contradicts their pledge to do no harm. Reflection on what is known should guide future action.