Table 3.

Multivariate analysis of prognostic factors for overall survival

Prognostic factors	Cox hazard model
	HR	95% CI	P value
Tumor stage (recurrent after surgery and stage VI/recurrent-after chemoradiotherapy)	5.00	0.64 to 39.06	0.125
Performance status (2–3/0–1)	3.18	1.35 to 7.51	0.008
PD-L1 expression (50%–100%/0%–49%)	1.24	0.56 to 2.78	0.596
Monocyte (median)	0.64	0.29 to 1.40	0.264
Neutrophil:lymphocyte ratio (median)	2.17	0.75 to 6.25	0.151
Albumin (median)	1.59	0.68 to 3.69	0.283
Multivariate model (median)	3.55	1.47 to 8.59	0.005

Each prognostic factor for overall survival was evaluated by multivariate Cox proportional hazard analysis.