Table 4

Recurrence-free proportion and clinicopathological characteristics of patients with stage I non-small cell lung cancer

Characteristic		No. of patients (%)	Recurrence-free proportion at 5 years (%)	Univariate p value^†
Overall		1485	83.4

Age (years)	≤65	722 (49)	86.8	0.001^*
Age (years)	>65	763 (51)	80	0.001^*

Gender	Women	608 (41)	87	<0.001^*
Gender	Men	877 (59)	80.8	<0.001^*

Smoking habits	Non-smoker	546 (37)	88.1	<0.001^*
Smoking habits	Ever smoker	939 (63)	80.5	<0.001^*

FEV₁/FVC (%)	≥70	1137 (77)	85	<0.001^*
	<70	339 (23)	77.4
	Not examined	9

CEA	Within normal range	995 (67)	85.7	<0.001^*
	Elevated	488 (33)	78.6
	Not examined	2

Tumour size (cm)	≤3.0	1001 (67)	87.9	<0.001^*
Tumour size (cm)	>3.0	484 (33)	78.6	<0.001^*

Histological type	Adenocarcinoma	1079 (73)	85.5	<0.001^*
Histological type	Non-adenocarcinoma	406 (27)	77.6	<0.001^*

Histological differentiation	Well differentiated	552 (37)	93.1	<0.001^*
Histological differentiation	Moderately/poorly differentiated	933 (63)	77	<0.001^*

Lymphatic permeation	Absent	1217 (82)	86.3	<0.001^*
Lymphatic permeation	Present	268 (18)	71.9	<0.001^*

Intratumoral vascular invasion	Absent	975 (66)	91.9	<0.001^*
Intratumoral vascular invasion	Present	510 (34)	67.3	<0.001^*

Visceral pleural invasion	Absent	1168 (79)	87.8	<0.001^*
Visceral pleural invasion	Present	317 (21)	66.6	<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.