Comparative efficacy and tolerability of adjuvant systemic treatments against resectable colon cancer: a network meta-analysis

BACKGROUND: Currently, 6-month oxaliplatin-based chemotherapy has been recommended as the preferred adjuvant treatment against high-risk stage 2 and stage 3 colon cancer patients. METHODS: Record retrieval was conducted in PubMed, Web of Science, Cochrane Central Register of Controlled Trials, American Society of Clinical Oncology and European Society for Medical Oncology meeting libraries from inception to November 2019. Regarding survival and tolerability, randomized controlled trials comparing different adjuvant systemic regimens against high-risk stage 2 and stage 3 colon cancer were eligible. Disease-free survival was primary endpoint. Network calculation was based on a random-effects model, and relative ranking of each node was numerically indicated by p score. RESULTS: A total of 30 trials were included, corresponding to 54,109 patients. Regarding disease-free survival, none of the analyzed regimens displayed significant superiority against common comparator 6-month capecitabine plus oxaliplatin (XELOX), while 12-month [network hazard ratio (HR) 0.81 (0.60–1.10); 0.79 (0.57–1.10)] and 3-month XELOX [0.95 (0.86–1.04); 0.93 (0.83–1.05)] were top-ranking regimens showing non-inferiority among overall and stage 3 patients. Moreover, by pairwise meta-analysis, 3-month XELOX demonstrated significant superiority against 6-month XELOX among low-risk stage 3 patients [pairwise HR 0.78 (0.63–0.97)]. Concerning adverse events, 3-month oxaliplatin-based chemotherapy was significantly better than the 6-month counterpart with respect to peripheral sensory neuropathy, thrombocytopenia and fatigue. The 12-month capecitabine monotherapy failed to display non-inferiority among other major adverse events. CONCLUSIONS: The 3-month XELOX treatment could be an alternative option of the 6-month regimen among low-risk stage 3 patients. Among high-risk stage 3 patients, 6-month oxaliplatin-based regimens still seem more competitive. In addition, clinical application of 12-month capecitabine monotherapy should be cautious, despite its top rankings, especially among non-Asian countries.