Neoadjuvant Chemoradiotherapy and Adjuvant Chemotherapy in Treating Patients Who Are Undergoing Surgical Resection for Locally Advanced Rectal Cancer

Pelvic radiation therapy given once daily 5 days a week for 6 weeks, 45 Gy in 25 fractions + boost of 5.4 Gy in 3 fractions for a total dose of 50.4 Gy.

825 mg/m\^2 q12 hours (1650 mg/m\^2/day) orally 5 days per week during radiotherapy.

600 mg/m\^2 q12 hours(1200 mg/m\^2/day) orally 5 days per week during radiotherapy.

50mg/m\^2 IV over 1 hour on days 1, 8, 22, and 29

50mg/m\^2 IV over 2 hours on days 1, 8, 15, 22, and 29

All patients will undergo surgery four to eight weeks following the completion of radiation therapy. The choice of procedure abdominoperineal resection (APR), low anterior resection (LAR), or LAR/coloanal anastomosis is at the discretion of the surgeon.

400 mg/m\^2 IV over 2 hours Day 1 (postoperatively) ,every 14 days, for nine 14-day cycles.

"5-fluorouracil bolus 400 mg/m\^2 IV push Day 1 (postoperatively), every 14 days, for nine 14-day cycles.~5-fluorouracil infusion 2400 mg/m\^2 IV continuous infusion over 46 hours, beginning day 1, every 14 days, for nine 14-day cycles."

85 mg/m\^2 IV over 2 hours Day 1 (postoperatively), every 14 days, for nine 14-day cycles.