Table 5.

C-index for the AJCC and upgraded staging system in advance NPC patients.

C-index	AJCC	Upgraded	Change(95%CI)	P
OS	0.606(0.546-0.666)	0.621(0.566-0.675)	-0.014(-0.045-0.015)	0.343
PFS	0.608(0.556-0.661)	0.619(0.571-0.667)	-0.011(-0.036-0.013)	0.380
DMFS	0.632(0.579-0.685)	0.627(0.570-0.684)	-0.005(-0.031-0.019)	0.680
LRFS	0.640(0.545-0.736)	0.649(0.553-0.745)	0.008(0.001-0.016)	0.023

OS, overall survival; PFS, progression-free survival; DMFS, distant metastasis free survival; LRFS, local recurrence-free survival.