Fig. 2

Kaplan–Meier curves of overall survival in distinct subgroups of NPC patients treated with CCRT or RT. The results show that CCRT significantly improved the 5-year overall survival rate for patients with a rT3–4 category disease (33.0% vs. 13.2%, P = 0.009), b stages III–IV NPC (34.3% vs. 13.2%, P = 0.006), c recurrence interval >30 months (49.0% vs. 20.6%, P = 0.017), and d tumor volume >26 cm3 (37.6% vs. 0%, P = 0.006) as compared with RT