Fig. 2

Kaplan–Meier curves for overall survival (a) and relapse-free survival (b). The rates of overall survival in the adjuvant chemotherapy and surgery-only groups are 86.0 and 81.4 %, respectively, while the rates of relapse-free survival are 69.3 and 73.9 %, respectively. The hazard ratio for death in the adjuvant chemotherapy group as compared to the surgery-only group is 0.891 (95 % confidence interval 0.54–1.46, p = 0.647). The hazard ratio for relapse in the adjuvant chemotherapy group is 1.226 (95 % confidence interval 0.887–1.695, p = 0.217). p values were calculated using the stratified log-rank test