Assessment of adjuvant chemotherapy benefits after complete mesocolic excision in patients with colon cancer: Reanalysis of data from the ESCME trial.

AIM: The benefits of adjuvant chemotherapy (AC) in colon cancer after complete mesocolic excision (CME) have not been evaluated sufficiently. We reanalysed the ESCME trial data to investigate the survival benefits and establish AC stratified indications. METHODS: The data of Stage II and III colon cancer patients who received CME in the ESCME trial were reanalysed. Patients were divided into AC and non-AC (NAC) groups. The primary outcomes measured were differences in 5-year cancer-specific survival and disease-free survival (DFS) between the groups. RESULTS: Of the 206 patients enrolled in the study, 125 patients (AC, 49; NAC, 76) had Stage II cancer and 111 (AC, 86; NAC, 25) had Stage III cancer. There were no significant differences in the adjusted 5-year cancer-specific survival and DFS between the AC and NAC groups. Poor differentiation (hazard ratio [HR] 2.947; 95% CI 1.218-7.131) and RAS mutation (HR 3.140; 95% CI 1.363-7.234) affected the 5-year DFS significantly in multivariate Cox regression analysis for Stage II and III cancer, respectively. In subgroup analysis, AC significantly improved 5-year DFS (HR 0.369; 95% CI 0.140-0.978) for Stage III cancer with lymphovascular/perineural invasion compared to NAC. CONCLUSION: The current indication and benefits of AC for colon cancer patients after CME should be re-evaluated. AC is more appropriate for Stage III cancer with lymphovascular/perineural invasion.