Table 2. Patient Characteristics of the study population.

Characteristics	Intrathoracic recurrence (n=489)	Extrathoracic recurrence (n=363)	Total (n=2,486)
Age (years), median [IQR]	62 [55−69]	61 [53−68]	61 [54−68]
Sex, n (%)
Male	338 (69.1)	238 (65.6)	1,586 (63.8)
Female	151 (30.9)	125 (34.4)	900 (36.2)
Grade, n (%)
Well	9 (1.9)	4 (1.2)	132 (5.5)
Moderate	243 (51.6)	172 (49.7)	1,288 (54.0)
Poor	219 (46.5)	170 (49.1)	967 (40.5)
Tumor size (cm), median (IQR)	4.0 (3.0−5.0)	4.1 (3.0−5.0)	3.0 (2.2−4.5)
Primary site, n (%)
Upper lobe	242 (49.5)	173 (47.7)	1,246 (50.1)
Middle lobe	34 (7.0)	23 (6.3)	164 (6.6)
Lower lobe	146 (29.9)	134 (36.9)	827 (33.3)
Main bronchus and trachea	40 (8.2)	25 (6.9)	168 (6.8)
Overlapping	27 (5.5)	8 (2.2)	81 (3.3)
Histology, n (%)
Adenocarcinoma	262 (53.6)	236 (65.0)	1,541 (62.0)
Squamous cell carcinoma	189 (38.7)	93 (25.6)	779 (31.3)
Others	38 (7.8)	34 (9.4)	166 (6.7)
T stage, n (%)
T1	75 (15.3)	52 (14.3)	582 (23.4)
T2	311 (63.6)	234 (64.5)	1,482 (59.6)
T3	67 (13.7)	53 (14.6)	291 (11.7)
T4	36 (7.4)	24 (6.6)	131 (5.3)
N stage, n (%)
N0	263 (53.8)	165 (45.5)	1,771 (71.2)
N1	98 (20.0)	90 (24.8)	360 (14.5)
N2	128 (26.2)	108 (29.8)	355 (14.3)
AJCC 8th stage, n (%)
I	171 (35.0)	87 (24.0)	1,298 (52.2)
II	132 (27.0)	125 (34.4)	626 (25.2)
IIIA	186 (38.0)	151 (41.6)	562 (22.6)
Surgical type, n (%)
Lobectomy/Bilobectomy	459 (93.9)	340 (93.7)	2,344 (94.3)
Sublobectomy	10 (2.0)	8 (2.2)	65 (2.6)
Pneumonectomy	20 (4.1)	15 (4.1)	77 (3.1)
Surgical method, n (%)
VATS	136 (27.8)	91 (25.1)	967 (38.9)
Open	350 (71.6)	268 (73.8)	1,481 (59.6)
Hybrid VATS	3 (0.6)	4 (1.1)	38 (1.5)

IQR, interquartile range; VATS, video-assisted thoracoscopic surgery.