Table 4. Univariate and multivariate Cox regression analysis.

Variable	Cases	Univariate Cox regression analysis				Multivariate Cox regression analysis
		Hazard ratio (95% CI)	χ2	P		Hazard ratio (95% CI)	χ2	P
Gender
Male	298	1	0.256	0.613
Female	52	0.922 (0.674–1.262)
Age (years)
≤72	277	1	6.239	0.012		1	4.711	0.030
>72	73	1.404 (1.076–1.833)				1.349 (1.030–1.769)
Primary site
Cervical esophagus	1	1	1.132	0.951
Upper third of esophagus	15	1.199 (0.156–9.187)
Middle third of esophagus	61	1.214 (0.168–8.786)
Lower third of esophagus	242	1.112 (0.156–7.943)
Overlapping lesion of esophagus	14	1.452 (0.188–11.194)
Thoracic esophagus	17	1.088 (0.143–8.249)
Grade
I	7	1	8.123	0.044		1	7.258	0.064
II	137	0.986 (0.460–2.115)				1.103 (0.510–2.387)
III	201	1.327 (0.623–2.826)				1.444 (0.674–3.093)
IV	5	2.060 (0.651–6.519)				2.308 (0.727–7.332)
Pathological type
Squamous cell carcinoma	111	1	0.827	0.661
Adenocarcinoma	207	1.106 (0.866–1.411)
Others	32	1.160 (0.762–1.765)
T stage
T1	97	1	8.679	0.034		1	8.152	0.043
T2	32	0.750 (0.490–1.148)				0.711 (0.464–1.090)
T3	134	0.729 (0.553–0.960)				0.738 (0.559–0.976)
T4	87	1.046 (0.774–1.414)				1.028 (0.757–1.397)
N stage
N0	63	1	6.548	0.088
N1	209	0.838 (0.624–1.127)
N2	45	1.246 (0.841–1.845)
N3	33	0.795(0.512–1.237)
Tumor size (mm)
≤63	204	1	2.849	0.091
>63	146	1.212 (0.970–1.515)
Race
White	276	1	1.665	0.645
Black	36	0.962 (0.666–1.391)
Asian	33	1.247 (0.858–1.813)
Others	5	0.805 (0.300–2.164)