Table 2.

Univariate and Multivariate analyses of the 5-year OS in N0 patients

Variable		Univariate			Multivariate
	HR	95% CI	p Value	HR	95% CI	p Value
Age			p < 0.001			p < 0.001
age < 55	Ref	/		Ref	/
55 ≤ age < 65	1.06	0.62–1.79		1.04	0.62–1.80
age ≥ 65	2.48	1.59–3.86		2.16	1.39–3.38
Sex			p = 0.06
female	Ref	/
male	0.63	0.39–1.02
Tumor location			p < 0.001
upper third	Ref	/
middle third	2.47	1.66–3.67
lower third	1.58	0.94–2.66
Tumor differentiation			p = 0.43
well differentiated	Ref	/
moderately differentiated	0.84	0.54–1.29
poorly differentiated or undifferentiated	0.92	0.58–1.45
Lymphovascular Invasion			p < 0.001			p < 0.001
no	Ref	/		Ref	/
yes	3.26	2.21–4.83		2.47	1.64–3.72
T-stage			p < 0.001			p < 0.001
T1	Ref	/		Ref	/
T2	1.73	0.93–3.22		1.54	0.83–2.88
T3	3.6	2.07–6.26		2.62	1.48–4.64
T4	3.8	2.23–6.73		3.18	1.82–5.59