Fig. 1

The effects of adjuvant radiotherapy on OS in different subgroups by Kaplan–Meier curves. A AJCC stages I–II and ACCI 2–4. B AJCC stages III–IV and ACCI 2–4. C AJCC stages I–II and ACCI ≥ 5. D AJCC stages III–IV and ACCI ≥ 5. ACCI, age-adjusted Charlson Comorbidity Index; OS, overall survival