Table 2

Recurrence-free proportion and clinicopathological characteristics of the entire cohort

Characteristic		No. of patients (%)	Recurrence-free proportion at 5 years (%)	Univariate p value^†
Overall
Age (years)	≤65	1149 (50)	69.2	0.388
Age (years)	>65	1146 (50)	67.9	0.388

Gender	Women	889 (38)	70.5	0.049^*
Gender	Men	1406 (62)	67.4	0.049^*

Smoking habits	Non-smoker	790 (34)	71.2	0.008^*
Smoking habits	Ever smoker	1505 (66)	67.2	0.008^*

FEV₁/FVC (%)	≥70	1726 (75)	69.3	0.038^*
	<70	559 (24)	65.9
	Not examined	10

CEA	Within normal range	1441 (63)	72	<0.001^*
	Elevated	851 (37)	62.6
	Not examined	3

Tumour size (cm)	≤3.0	1239 (54)	79.5	<0.001^*
Tumour size (cm)	>3.0	1056 (46)	55.3	<0.001^*

Histological type	Adenocarcinoma	1546 (67)	69.8	0.009^*
Histological type	Non-adenocarcinoma	749 (33)	66.1	0.009^*

Histological differentiation	Well differentiated	628 (27)	86.7	<0.001^*
Histological differentiation	Moderately/poorly differentiated	1667 (73)	61	<0.001^*

Lymphatic permeation	Absent	1595 (69)	77.7	<0.001^*
Lymphatic permeation	Present	700 (31)	49.1	<0.001^*

Intratumoral vascular invasion	Absent	1151 (50)	85	<0.001^*
Intratumoral vascular invasion	Present	1144 (50)	51.5	<0.001^*

Visceral pleural invasion	Absent	1537 (67)	77.9	<0.001^*
Visceral pleural invasion	Present	758 (33)	48.6	<0.001^*

N status	N0	1640 (71)	80.7	<0.001^*
N status	N1 or N2	655 (29)	36.8	<0.001^*

↵* Indicates significance.
↵† Log rank test.
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.