Seven RCTs were included in the review (n=2,095 patients). All trials had a Jadad score of 2 (considered poor quality). Random allocation concealment was rated unclear in all trials.
Oxaliplatin was associated with a significantly higher response rate (partial and complete) compared to irinotecan (RR 0.77, 95% CI 0.68 to 0.87; I2=23.6%; figures taken from the forest plot, which differed to those reported in the text; seven RCTs). Oxaliplatin was associated with a longer mean overall survival compared with irinotecan (WMD 2.04 months, 95% CI -3.54 to -0.54; n=1,875; six RCTs).
The incidence of grade 3/4 toxicity (nausea/emesis, diarrhoea, alopecia) was higher in the irinotecan group compared with the oxaliplatin group: nausea/emesis (RR 1.94, 95% CI 1.22 to 3.09; seven RCTs); diarrhoea (RR 1.71, 95% CI 1.34 to 2.18; seven RCTs); and alopecia (RR 14.56, 95% CI 4.11 to 51.66; n=791 patients; two RCTs). No differences between groups were found in the incidence of mucositis and febrile neutropenia.
However, the incidence of neurotoxicity (RR 0.06, 95% CI 0.03 to 0.14; n=2,095; seven RCTs), neutropenia (RR 0.70, 95% CI 0.55 to 0.91; seven RCTs) and thrombocytopenia (RR 0.18, 95% CI 0.05 to 0.61; n=1,151; four RCTs) were lower in the irinotecan group compared with the oxaliplatin group. No evidence of heterogeneity was found except for neutropenia.
There were no differences between groups in the incidence of dehydration, anaemia, or fatigue.