Table 3

Univariate and multivariable analysis of risk factors for recurrence in the entire cohort

Variables		Univariate analysis			Multivariate analysis
Variables		HR	95% CI	p Value	HR	95% CI	p Value
Age (years)	≤65	1
Age (years)	>65	1.059	0.912 to 1.229	0.453	Not included in multivariable model

Gender	Women	1
Gender	Men	1.159	0.994 to 1.352	0.06	Not included in multivariable model

Smoking habits	Non-smoker	1
Smoking habits	Ever smoker	1.239	1.057 to 1.452	0.008^*	Not included in multivariable model

FEV₁/FVC (%)	≥70	1
FEV₁/FVC (%)	<70	1.203	1.016 to 1.424	0.032^*	Not included in multivariable model

CEA	Within normal range	1
CEA	Elevated	1.434	1.233 to 1.667	<0.001^*	Not included in multivariable model

Tumour size (cm)	≤3.0	1			1
Tumour size (cm)	>3.0	2.619	2.244 to 3.057	<0.001^*	1.478	1.247 to 1.752	<0.001^*

Histological type	Adenocarcinoma	1			1
Histological type	Non-adenocarcinoma	1.225	1.047 to 1.434	0.011^*	1.346	1.140 to 1.159	<0.001^*

Histological differentiation	Well differentiated	1			1
Histological differentiation	Moderately/poorly differentiated	3.354	2.696 to 4.173	<0.001^*	1.495	1.171 to 1.910	0.001^*

Lymphatic permeation	Absent	1			1
Lymphatic permeation	Present	2.736	2.357 to 3.177	<0.001^*	1.284	1.089 to 1.513	0.003^*

Intratumoral vascular invasion	Absent	1			1
Intratumoral vascular invasion	Present	4.061	3.420 to 4.821	<0.001^*	1.866	1.516 to 2.298	<0.001^*

Visceral pleural invasion	Absent	1			1
Visceral pleural invasion	Present	2.88	2.480 to 3.345	<0.001^*	1.463	1.242 to 1.722	<0.001^*

N status	N0	1			1
N status	N1 or N2	4.722	4.060 to 5.492	<0.001^*	2.59	2.181 to 3.076	<0.001^*

↵* Indicates significance.
CEA, preoperative serum carcinoembryonic antigen level (normal upper limit 5 ng/ml); FEV₁/FVC, forced expiratory volume in 1 s to forced vital capacity ratio; HR, HR for recurrence.