Fig. 1.
Kaplan–Meier estimates of overall survival by treatment era. The unadjusted hazard ratio for death among patients in post-2004 group, as compared with those in pre-2004 group, was 0.75 (95 % CI 0.53–1.06; p = 0.1). The Hazard ratio was 0.64 (95 % CI 0.44–0.91, p = 0.0145) after adjusting for age, KPS and type of surgical procedure (a 40 % reduction of hazard of death)