Patients will undergo surgery-either a low anterior resection, abdominoperineal resection or local excision. All patients will be offered postoperative adjuvant chemotherapy consisting of 5-Fluorouracil (F-FU) 350 mg/m2/day i.v. for 5 days administered every 28 days times four cycles. Immediately prior to the administration of 5-FU, leucovorin will be administered at a dose of 20 mg/m2/day i.v. push daily for 5 days every 28 days times four cycles.