Table 3. Univariate analyses of the overall survival and disease-free survival of the matched cohort.

Variables	Prognostic factors for overall survival			Prognostic factors for disease-free survival
	HR (95% CI)	P value		HR (95% CI)	P value
Age	1.06 (1.02–1.10)	0.005*		1.03 (0.99–1.06)	0.12
Gender
Female	Reference			Reference
Male	0.51 (0.21–1.24)	0.14		0.70 (0.48–1.03)	0.07
Smoke
Never	Reference			Reference
Current or former	0.53 (0.26–1.11)	0.09		0.38 (0.20–0.73)	0.004*
Pathologic type
Squamous	Reference			Reference
Others	2.20 (1.10–4.42)	0.03*		2.44 (1.33–4.48)	0.004*
Neoadjuvant therapy
No	Reference			Reference
Yes	0.58 (0.27–1.25)	0.17		0.81 (0.44–1.51)	0.51
Pathologic T stage
T1	Reference			Reference
T2	2.01 (0.62–6.59)	0.25		1.92 (0.68–5.40)	0.22
T3	2.11 (0.53–8.45)	0.29		1.83 (0.54–6.26)	0.34
T4	2.80 (0.74–10.60)	0.13		3.37 (1.07–10.61)	0.04*
Pathologic N stage
N0	Reference			Reference
N1	3.57 (1.47–8.66)	0.005*		2.91 (1.43–5.92)	0.003*
N2	4.94 (1.87–13.02)	0.001*		3.74 (1.68–8.34)	0.001*
Resection margins
R0	Reference			Reference
Others	3.02 (1.57–5.82)	0.001*		3.9 (2.12–7.18)	<0.001*
Approach
SL	Reference			Reference
ESL	0.44 (0.21–0.92)	0.03*		0.43 (0.22–0.83)	0.01*

*, P<0.05. HR, hazard ratio; CI, confidence interval.