Table II. The correlation of clinical factors and incidence of pulmonary metastases in 298 patients with surgically treated colorectal liver metastases.

Factors	Pulmonary recurrence
	Yes		No
Clinical factors	n=127	%	n=171	%	p value
Gender					0.434
Male	70	55	102	60
Female	57	45	69	40
Age (years)					0.165
< 60	63	50	71	42
≤ 60	64	50	100	56
UICC TNM staging					0.305
Stage I and II	29	23	49	29
Stage III	44	35	48	28
Stage IV	44	35	53	31
Unknown	10	8	21	12
Primary histological differentiation					0.752
Well/moderate	89	70	121	71
Poor	13	10	21	12
Unknown	25	20	29	17
Treatment time of liver metastases					0.582
Synchronous	34	27	41	24
Metachronous	93	73	130	76
No. of liver metastases					0.300
1	42	33	61	36	0.140*
2–3	42	33	66	39
> 3	43	34	44	25
Largest size of liver metastases					0.427
1–3 cm	53	42	80	47	0.656*
4–6 cm	43	33	46	27
> 7 cm	31	24	45	26
Preoperative CEA level (ng/ml)					0.081
≤ 5.0	24	19	53	31
5.01–100.0	62	49	78	46
> 100.0	21	16	23	13
Unknown	20	16	17	10
Postoperative CEA level (ng/ml)					0.201
≤ 5.0	95	75	130	76
> 5.0	25	20	24	14
Unknown	7	5	17	10
Operation type					0.004
Resection only	56	44	104	61
Cryotherapy±resection	71	56	67	39

* Analysed using Wilcoxon rank test.