Fig. 2

The effects of adjuvant radiotherapy on PFS 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; PFS, progression-free survival