Table 1. Patient characteristics of enrolled patients (N=1,308).

Variables	All (N=1,308)	Adenocarcinomas (N=1,146, 87.6%)	Squamous cell carcinomas (N=162, 12.4%)	P value
Mean age (SD), years	60.3 (9.3)	59.7 (9.4)	64.5 (7.6)	<0.001
Sex, n (%)				<0.001
Male	634 (48.5)	475 (41.4)	159 (98.1)
Female	674 (51.5)	671 (58.6)	3 (1.9)
Smoking history, n (%)				<0.001
Smokers/ever	395 (30.2)	270 (23.7)	123 (75.9)
Never	913 (69.8)	874 (76.3)	39 (24.1)
8th clinical T status, n (%)				<0.001
cT1a	204 (15.6)	196 (17.1)	8 (4.9)
cT1b	620 (47.4)	572 (49.9)	48 (29.6)
cT1c	293 (22.4)	263 (22.9)	30 (18.5)
cT2 and above	191 (14.6)	115 (10.1)	76 (47.0)
Tumour location, n (%)				<0.001
Central	245 (18.7)	130 (11.3)	115 (71.0)
Peripheral	1,063 (81.3)	1016 (88.7)	47 (29.0)
Lobes of lung, n (%)				<0.001
Left upper lobe	305 (23.3)	267 (23.3)	38 (23.5)
Left lower lobe	211 (16.1)	169 (14.7)	42 (25.9)
Right upper lobe	417 (31.9)	385 (33.6)	32 (19.8)
Right middle lobe	100 (7.6)	96 (8.4)	4 (2.5)
Right lower lobe	275 (21.0)	229 (20.0)	46 (28.4)
Surgical type, n (%)				<0.001
VATS	1230 (94.0)	1,104 (96.3)	126 (77.8)
Open surgery	78 (6.0)	42 (3.7)	36 (22.2)
8th pathological T status, n (%)				<0.001
pT1a	191 (14.6)	181 (15.8)	10 (6.2)
pT1b	625 (47.8)	591 (51.6)	34 (21.0)
pT1c	249 (19.0)	214 (18.7)	35 (21.6)
pT2 and above	243 (18.6)	160 (13.9)	83 (51.2)
8th pathological N status, n (%)				<0.001
pN0	1,150 (87.9)	1,027 (89.6)	123 (75.9)
pN1	76 (5.8)	49 (4.3)	27 (16.7)
pN2	82 (6.3)	70 (6.1)	12 (7.4)
8th pathological stage, n (%)				<0.001
IA	993 (75.9)	928 (81.0)	65 (40.1)
IB	56 (4.3)	30 (2.6)	26 (16.1)
IIA	77 (5.9)	64 (5.6)	13 (8.0)
IIB	75 (5.7)	46 (4.0)	30 (18.5)
IIIA	95 (7.3)	70 (6.1)	24 (14.8)
IIIB	12 (0.9)	8 (0.7)	4 (2.5)

VATS, video-assisted thoracoscopic surgery.