Table III.

Univariate and multivariate Cox regression analyses of factors affecting the overall survival time of patients with esophageal squamous cell carcinoma (n=246).

A, Univariate analysis
Variable	HR	95% CI	P-value
PD-L1
Positive vs. negative	1.152	0.787–1.684	0.467
Sex
Male vs. female	1.106	0.624–1.961	0.730
Age (years)
≥65 vs. <65	1.080	0.700–1.665	0.729
Smoking history
Yes vs. no	1.388	0.894–2.156	0.144
Alcohol drinking
Yes vs. no	1.100	0.746–1.621	0.631
CCI
Low vs. moderate vs. high	1.176	0.741–1.866	0.491
Vessel invasion
Yes vs. no	1.466	0.987–2.174	0.058
Tumor differentiation
Well vs. moderate vs. poor	1.055	0.814–1.366	0.688
Tumor location
Lower vs. middle vs. upper	1.242	0.907–1.704	0.177
T stage
T1-2 vs. T3-4	1.100	0.741–1.631	0.637
N stage
N0-1 vs. N2-3	1.613	1.152–2.257	0.005
TNM stagea
II vs. III	1.623	1.151–2.288	0.006
Chemotherapy
Yes vs. no	1.038	0.741–1.456	0.827
Radiotherapy
Yes vs. no	1.168	0.838–1.631	0.359
B, Multivariate analysis
Variable	HR	95% CI	P-value
PD-L1
Positive vs. negative	1.053	0.698–1.589	0.804
Sex
Male vs. female	1.051	0.545–2.028	0.882
Age, years
≥65 vs. <65	1.049	0.652–1.690	0.843
Smoking history
Yes vs. no	1.658	1.002–2.740	0.049
Alcohol drinking
Yes vs. no	1.454	0.935–2.262	0.097
CCI
Low vs. moderate vs. high	1.053	0.664–1.669	0.826
Vessel invasion
Yes vs. no	1.685	1.128–2.518	0.011
Tumor differentiation
Well vs. moderate vs. poor	1.104	0.838–1.456	0.483
Tumor location
Lower vs. middle vs. upper	1.248	0.908–1.718	0.172
T stage
T1-2 vs. T3-4	1.068	0.665–1.717	0.785
N stage
N0-1 vs. N2-3	1.709	1.215–2.404	0.002
TNM stagea
II vs. III	1.350	0.777–2.347	0.287
Chemotherapy
Yes vs. no	1.092	0.740–1.611	0.659
Radiotherapy
Yes vs. no	1.183	0.838–1.672	0.339

^aTNM staging was performed according to the 7th American Joint Committee on Cancer guidelines. CCI, Charlson comorbidity index; HR, hazard ratio; CI, confidence interval; PD-L1, programmed death-ligand 1; TNM, tumor-node-metastasis; T stage, tumor stage; N stage, node stage.