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

Table 3 Univariate analysis of factors associated with disease-free survival

Variable	HR	95%CI	P value
Age	0.984	0.957-1.012	0.271
Sex
Male	Ref
Female	1.000	0.614-1.628	0.999
Location of primary tumor
Rectum	Ref
Right	0.892	0.499-1.593	0.698
Left	0.678	0.362-1.271	0.226
Regional LN metastasis
No	Ref
Yes	2.324	1.348-4.008	0.002a
Synchronous liver metastasis
No	Ref
Yes	0.820	0.502-1.342	0.431
Time of diagnosis of liver metastasis, %
Synchronous	Ref
Metachronous
Disease-free interval < 12 mo	1.066	0.452-2.509	0.884
Disease-free interval ≥ 12 mo	0.765	0.446-1.312	0.330
Preoperative CEA level
< 200 ng/mL	Ref
≥ 200 ng/mL	1.064	0.426-2.657	0.894
Systemic chemotherapy before liver resection
No	Ref
Yes	1.724	0.779-3.818	0.179
Number of liver metastases
< 5 lesions	Ref
≥ 5 lesions	3.138	1.409-6.987	0.005a
Size of the largest liver lesion
< 4 cm	Ref
≥ 4 cm	1.272	0.763-2.121	0.355
Surgical margin
Clear	Ref
Involved	1.110	0.616-2.000	0.728
Concurrent ablation
No	Ref
Yes	1.705	0.777-3.739	0.183
Operative approach
Laparoscopic	Ref
Open	0.785	0.480-1.285	0.336
Intraoperative blood loss, %
< 500 mL	Ref
≥ 500 mL	1.305	0.808-2.107	0.276
Requirement of blood transfusion, %
No	Ref
Yes	1.037	0.585-1.840	0.900

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