Oxaliplatin, Leucovorin, and Fluorouracil Before and After Radiation Therapy and Surgery in Treating Patients With Rectal Cancer That Can Be Removed by Surgery

RATIONALE: Drugs used in chemotherapy, such as oxaliplatin, leucovorin, and fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving chemotherapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Giving chemotherapy after surgery may kill any tumor cells that remain after surgery.
PURPOSE: This phase II trial is studying giving oxaliplatin, leucovorin, and fluorouracil together, before and after radiation therapy and surgery in treating patients with rectal cancer that can be removed by surgery.