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

Table 4 Multivariate analysis of factors associated with overall survival

Variable	Adjusted HR	95%CI	P value
Age	1.039	0.999-1.080	0.054
Sex
Male	Ref
Female	1.874	0.984-3.572	0.056
Location of primary tumor
Rectum	Ref
Right	1.180	0.572-2.435	0.654
Left	0.943	0.427-2.084	0.884
Regional LN metastasis
No	Ref
Yes	1.955	1.031-3.707	0.040a
Time of diagnosis of liver metastasis, %
Synchronous	Ref
Metachronous
Disease-free interval < 12 mo	1.192	0.431-3.295	0.735
Disease-free interval ≥ 12 mo	0.668	0.324-1.378	0.275
Synchronous extrahepatic metastasis
No	Ref
Yes	2.454	0.308-19.572	0.397
Preoperative CEA level
< 200 ng/mL	Ref
≥ 200 ng/mL	0.495	0.137-1.785	0.282
Systemic chemotherapy before liver resection
No	Ref
Yes	1.031	0.363-2.929	0.954
Number of liver metastases
< 5 lesions	Ref
≥ 5 lesions	2.962	1.174-7.473	0.022a
Size of the largest liver lesion
< 4 cm	Ref
≥ 4 cm	2.983	1.343-6.625	0.007a
Concurrent ablation
No	Ref
Yes	1.241	0.436-3.533	0.685
Operative approach
Laparoscopic	Ref
Open	1.655	0.873-3.137	0.123
Requirement of blood transfusion, %
Yes	Ref
No	0.681	0.320-1.451	0.320

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