Neoadjuvant FOLFOX6 Chemotherapy With or Without Radiation in Rectal Cancer

RATIONALE: Preoperative 5-Fu based chemoradiation has become standard treatment for stage 2/3 rectal cancer. However whether these patients, especially T3N0-1M0 patients, really need radiation for local control after total mesentery excision being applied in routine practice is still unknown. And whether new drugs adding in can achieve better local and distant control is worth investigating. PURPOSE: This randomized phase II trial is studying 5Fu based radiation therapy or FOLFOX based radiation or FOLFOX alone, comparing them to see how well they work when given before surgery in treating patients with intermediate risk resectable rectal cancer. It is not yet known whether 5-Fu based or FOLFOX based radiation therapy or even FOLFOX alone is more effective in treating rectal cancer.