Prognostic factors of survival and a new scoring system for liver resection of colorectal liver metastasis

Table 5 Multivariate analysis of factors associated with disease-free survival

Variable	Adjusted HR	95%CI	P value
Age	0.988	0.955-1.021	0.467
Sex
Male	Ref
Female	1.022	0.579-1.805	0.941
Location of primary tumor
Rectum	Ref
Right	1.044	0.538-2.025	0.899
Left	0.635	0.302-1.337	0.232
Regional LN metastasis
No	Ref
Yes	2.234	1.219-4.093	0.009a
Time of diagnosis of liver metastasis, %
Synchronous	Ref
Metachronous
Disease-free interval < 12 mo	1.392	0.536-3.615	0.496
Disease-free interval ≥ 12 mo	0.846	0.445-1.610	0.611
Synchronous extrahepatic metastasis
No	Ref
Yes	9.716	2.034-46.413	0.004a
Preoperative CEA level
< 200 ng/mL	Ref
≥ 200 ng/mL	0.734	0.238-2.263	0.591
Systemic chemotherapy before liver resection
No	Ref
Yes	1.878	0.774-4.557	0.163
Number of liver metastases
< 5 lesions	Ref
≥ 5 lesions	2.753	1.052-7.205	0.039a
Size of the largest liver lesion
< 4 cm	Ref
≥ 4 cm	1.690	0.847-3.374	0.137
Concurrent ablation
No	Ref
Yes	0.788	0.267-2.324	0.666
Operative approach
Laparoscopic	Ref
Open	1.000	0.572-1.748	1.000
Requirement of blood transfusion, %
Yes	Ref
No	0.692	0.342-1.399	0.306

^aP < 0.05. CEA: Carcinoembryonic antigen; CI: Confidence interval; HR: Hazard ratio; LN: Lymph node; Ref: Reference.