Combination radiation therapy and chemotherapy is now the treatment of choice for squamous cell carcinoma of the anus. The area of the primary lesion is biopsied, and the patient begins radiotherapy to the pelvis. If inguinal lymph nodes are enlarged, they are also biopsied, usually by fine needle aspiration, and if positive, they are included in the field of radiation. Following radiation therapy, patients receive intravenous 5-FU and mitomycin C. Patients who fail therapy have limited options, including additional chemotherapy or radiotherapy. Salvage therapy may also include abdominoperineal resection (APR), lymphadenectomy, or a diveing colostomy, depending on the nature of the recurrence.