The addition of oxaliplatin to weekly FULV significantly improved DFS in patients with stage II and III colon cancer. FLOX can be recommended as an effective option in clinical practice.

Purpose The optimal chemotherapy regimen administered concurrently with preoperative radiation therapy (RT) for patients with rectal cancer is unknown. National Surgical Adjuvant Breast and Bowel Project trial R-04 compared four chemotherapy regimens administered concomitantly with RT. Patients and Methods Patients with clinical stage II or III rectal cancer who were undergoing preoperative RT (45 Gy in 25 fractions over 5 weeks plus a boost of 5.4 Gy to 10.8 Gy in three to six daily fractions) were randomly assigned to one of the following chemotherapy regimens: continuous intravenous infusional fluorouracil (CVI FU; 225 mg/m2, 5 days per week), with or without intravenous oxaliplatin (50 mg/m2 once per week for 5 weeks) or oral capecitabine (825 mg/m2 twice per day, 5 days per week), with or without oxaliplatin (50 mg/m2 once per week for 5 weeks). Before random assignment, the surgeon indicated whether the patient was eligible for sphincter-sparing surgery based on clinical staging. The surgical end points were complete pathologic response (pCR), sphincter-sparing surgery, and surgical downstaging (conversion to sphincter-sparing surgery). Results From September 2004 to August 2010, 1,608 patients were randomly assigned. No significant differences in the rates of pCR, sphincter-sparing surgery, or surgical downstaging were identified between the CVI FU and capecitabine regimens or between the two regimens with or without oxaliplatin. Patients treated with oxaliplatin experienced significantly more grade 3 or 4 diarrhea (P < .001). Conclusion Administering capecitabine with preoperative RT achieved similar rates of pCR, sphincter-sparing surgery, and surgical downstaging compared with CVI FU. Adding oxaliplatin did not improve surgical outcomes but added significant toxicity. The definitive analysis of local tumor control, disease-free survival, and overall survival will be performed when the protocol-specified number of events has occurred.

Continuous infusion 5-FU produced outcomes for local-regional control, DFS, and OS similar to those obtained with oral capecitabine combined with radiation. This study establishes capecitabine as a standard of care in the pre-operative rectal setting. Oxaliplatin did not improve the local-regional failure rate, DFS, or OS for any patient risk group but did add considerable toxicity.