Cochrane systematic review and meta-analysis of adjuvant chemotherapy for stage II colon cancer.

3548 Background: Colon cancer is potentially curable by surgery in the early stages of the disease. Adjuvant chemotherapy improves disease-free and overall survival in patients with stage III disease, but the magnitude of benefit in stage II colon cancer is less clear. A previous Cochrane systematic review and meta-analysis (SR/MA) found improved disease-free, but not overall survival (Figueredo et al., 2008). An updated SR/MA was performed to determine the effects of adjuvant chemotherapy on disease-free and overall survival in patients with stage II colon cancer. Methods: Relevant databases (MEDLINE, EMBASE, and Cochrane) were independently searched by all authors, using the same search strategy employed in the original study (1/1988 to 9/2012). Randomized trials containing data on stage II colon cancer patients undergoing adjuvant 5-fluorouracil (5FU) chemotherapy versus observation were included. Pooled results were expressed as hazard ratios (HR) whenever possible, or risk ratios (RR), with 95% confidence intervals (95%CI) using a random effects model. Results: Seven studies were identified, and included in the final SR/MA. Six of the 7 studies were included in the disease-free survival analysis (n=4587). Adjuvant 5FU was associated with better disease-free survival (RR 0.84 (95%CI 0.75-0.94)). All 7 studies (n=5353) were included in the overall survival analysis showing an improvement with adjuvant 5FU (HR 0.87 (95%CI 0.78-0.97)). There was no evidence of heterogeneity across the studies (I 2 = 0% for all analyses). Conclusions: In stage II colon cancer, adjuvant 5FU chemotherapy statistically improves both disease-free and overall survival. Our SR/MA demonstrates, for the first time, an overall survival advantage with adjuvant chemotherapy in stage II colon cancer.