Table 2.

Pulmonary metastases characteristics in each group (initial and second pulmonary metastasectomy)

Characteristics		The initial pulmonary metastasectomy n = 126	The second pulmonary metastasectomy n = 26	p value
Diagnosis period, n (%)		Synchronous 41 (32.5) Metachronous 85 (67.5)	–	–
Number of pulmonary metastasis, n (%)		1: 89 (70.6) 2: 17 (13.5) 3: 12 (9.5) 4: 3 (2.4) 5: 2 (1.6)	1: 16 (61.5) 2: 7 (26.9) 3: 1 (3.8) 4: 2 (7.7)	0.36
	Solitary	89 (70.6)	16 (61.5)	0.27
	Multiple	34 (27.0)	10 (38.5)
Location, n (%)	Unilateral	108 (85.7)	23 (88.5)	0.71
	Bilateral	18 (14.3)	3 (11.5)
Disease free interval (days), median [range]		541.5 [0–4664]	409 [27–1334]	0.13
Maximum tumor size (mm), median [range]		12.0 [5–70]	12.0 [8–40]	1.00
Mediastinal lymph node metastasis, n (%)	Negative	117 (92.9)	25 (96.2)	0.95
	Positive	5 (4.0)	1 (3.8)
Preoperative CEA level, n (%)	Normal	86 (68.3)	15 (57.7)	0.61
	Elevated	36 (28.6)	8 (30.8)
Preoperative CA19-9 level, n (%)	Normal	97 (77.0)	21 (80.8)	0.74
	Elevated	12 (9.5)	2 (7.7)
Chemotherapy before operation, n (%)	Yes	28 (22.2)	9 (34.6)	0.09
	No	96 (76.2)	15 (57.7)
Chemotherapy after operation, n (%)	Yes	40 (31.7)	9 (34.6)	0.50
	No	74 (58.7)	12 (46.2)
Recurrence after pulmonary metastasectomy, n (%)	Yes	67 (53.2)	17 (65.4)	0.07
	No	59 (46.8)	7 (26.9)
Recurrent organ, n (%)		Lung 47 (37.3) Liver 12 (9.5) Abdominal lymph node 6 (4.8) Pelvic local recurrence 6 (4.8) Bone 5 (4.0) Brain 5 (4.0) Peritoneal dissemination 3 (2.4) Pleural dissemination 2 (1.6) Bone marrow 1 (0.8) Adrenal 1 (0.8)	Lung 13 (46.4) Pleural dissemination 2 (7.2) Thoracic lymph node 2 (7.2) Liver 1 (3.6) Bone 1 (3.6) Brain 1 (3.6) Pancreas 1 (3.6)

CEA carcinoembryonic antigen level (normal upper limit at 5 ng/ml), CA19-9 carbohydrate antigen 19-9 level (normal upper limit at 37 ng/ml)

^*p < 0.05; ^**p < 0.01; ^***p < 0.001