摘要Background To compare clinical efficacy and toxicity of irinotecan combined with 5-fluorouracil and leucovorin with those of oxaliplatin combined with 5-fiuorouracil and leucovorin as first-line therapy for advanced colorectal cancer.Methods Literature search was performed by keywords "irinotecan", "oxaliplatin" and "colorectal cancer" on all randomized controlled trails reported on irinotecan versus oxaliplatin combined with 5-fluorouracil and leucovorin as first-line therapy for advanced colorectal cancer in MEDLINE, OVID, Springer, Cochrane Controlled Trials Register (CCTR) and CBMdisc (Chinese Biology and Medicine disc) before January 2010. Two authors drew the details of trial design, characteristics of patients, outcomes, and toxicity from the studies included. Data analysis was performed by RevMan 4.2.Results According to the screening criteria, 7 clinical studies with 2095 participants of advanced colorectal cancer were included in this meta analysis. The baseline characteristics of irinotecan group were similar to those of oxaliplatin group.The response rate of oxaliplatin group was higher than that of irinotecan group (relative risk (RR)=0.82, 95% confidence interval (95%CI) (0.70, 0.96), P=0.01), and the median overall survival of oxaliplatin group was longer by 2.04 months than that of irinotecan group (95%CI (-3.54, -0.54), P=0.008). In the comparison of grade 3-4 toxicity between the two groups, the incidences of nausea, emesis, diarrhoea and alopecia in irinotecan group were higher than those in oxaliplatin group (RR=1.94, 95%CI(1.22, 3.09), P=0.005; 1.71, 95%CI (1.34, 2.18), P ＜0.001; 14.56, 95%CI (4.11,51.66), P ＜0.0001), respectively. However, the incidence of neurotoxicity, neutropenia and thrombocytopenia in irinotecan group were lower than those in oxaliplatin group (RR=0.06, 95%CI(0.03, 0.14), P ＜0.00001; 0.70, 95%CI(0.55, 0.91), P=0.006; 0.18, 95%CI(0.05, 0.61), P=0.006), respectively.Conclusions Both irinotecan and oxaliplatin combined with 5-fluorouracil and leucovorin were effective in the first-line therapy of advanced colorectal cancer. However, the combined regimen of oxaliplatin plus 5-fluorouracil and leucovorin is more excellent. Irinotecan trended to result in more gastrointestinal tract reactions than oxaliplatin did, but the myelosuppression and neurotoxicity were more frequent in oxaliplatin regimen than irinotecan regimen.