PROSPECT: Chemotherapy Alone or Chemotherapy Plus Radiation Therapy in Treating Patients With Locally Advanced Rectal Cancer Undergoing Surgery

The standard treatment for locally advanced rectal cancer involves chemotherapy and radiation, known as 5FUCMT, (the chemotherapy drugs 5-fluorouracil/capecitabine and radiation therapy) prior to surgery. Although radiation therapy to the pelvis has been a standard and important part of treatment for rectal cancer and has been shown to decrease the risk of the cancer coming back in the same area in the pelvis, some patients experience undesirable side effects from the radiation and there have been important advances in chemotherapy, surgery, and radiation which may be of benefit. The purpose of this study is to compare the effects, both good and bad, of the standard treatment of chemotherapy and radiation to chemotherapy using a combination regimen known as FOLFOX, (the drugs 5-fluorouracil (5-FU), oxaliplatin and leucovorin) and selective use of the standard treatment, depending on response to the FOLFOX. The drugs in the FOLFOX regimen are all FDA (Food and Drug Administration) approved and have been used routinely to treat patients with advanced colorectal cancer.

OUTLINE: This is a multicenter, phase II/III study. Patients are stratified according to ECOG performance status (0 or 1 vs 2) and randomized to 1 of 2 treatment regimens. Patients will receive full supportive care while on this study. OBJECTIVES: Primary 1. Phase II component: To assure that neoadjuvant FOLFOX followed by selective use of 5FUCMT group (Group 1) maintains the current high rate of pelvic R0 resection and is consistent with non-inferiority for time to local recurrence (TLR). 2. Phase III component: To compare neoadjuvant FOLFOX followed by selective use of 5FUCMT (Group 1) to standard 5FUCMT (Group 2) with respect to the primary endpoint of the Disease-Free Survival (DFS). Secondary 1. To determine if the neoadjuvant FOLFOX followed by selective use of 5FUCMT (Group 1) is non-inferior to the standard group 5FUCMT (Group 2) with respect to the proportion of patients who achieve a pathologic complete response (pCR) at the time of surgical resection. 2. To determine if the neoadjuvant FOLFOX followed by selective use of 5FUCMT (Group 1) is non-inferior to the standard 5FUCMT (Group 2) with respect to overall survival. 3. To evaluate and compare the adverse event profile and surgery complications between two groups. 4. To estimate the proportion of patients in the selective group (Group 1) who receive: 1) pre-operative 5FUCMT; 2) post-operative 5FUCMT; 3) either pre- or post-operative 5FUCMT. 5. To determine if the neoadjuvant FOLFOX followed by selective use of 5FUCMT (Group 1) is non-inferior to the standard 5FUCMT (Group 2) with respect to Local Recurrence (TLR) 6. To determine if the neoadjuvant FOLFOX followed by selective use of 5FUCMT (Group 1) is non-inferior to the standard 5FUCMT (Group 2) with respect to Neoadjuvant Response Score (NAR) Event monitoring of patients will continue up to 8 years post randomization.