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

Table 1 Clinicopathological data of patients

Characteristic	Total (n = 98)
Age in yr, median (IQR)	65.5 (59-72)
Sex, n (%)
Male	62 (63.3)
Female	36 (36.7)
Location of primary colorectal tumor, n (%)
Right	26 (26.5)
Left	40 (40.8)
Rectum	32 (32.7)
LN involvement in primary tumor, n (%)
Yes	62 (63.3)
No	36 (36.7)
Time of diagnosis of liver metastasis, n (%)
Synchronous	59 (60.2)
Metachronous
Disease-free interval < 12 mo	9 (9.2)
Disease-free interval ≥ 12 mo	30 (30.6)
Synchronous extrahepatic metastasis, n (%)
Yes	4 (4.1)
No	94 (95.9)
Preoperative CEA level in ng/mL, n (%)
< 200	90 (91.8)
≥ 200	6 (6.1)
Systemic chemotherapy before liver resection, n (%)
Yes	9 (9.2)
No	89 (90.8)
Number of liver metastases, n (%)
< 5 lesions	91 (92.9)
≥ 5 lesions	7 (7.1)
Size of largest liver metastasis, n (%)
< 4 cm	67 (68.4)
≥ 4 cm	28 (28.6)
Surgical margin, n (%)
Positive	19 (19.4)
Negative	78 (79.6)
Concurrent ablation, n (%)
No	90 (91.8)
Yes	8 (8.2)
Operative approach, n (%)
Laparoscopic	57 (58.2)
Open	41 (41.8)
Type of hepatectomy, n (%)
Minor	61 (62.2)
Major	37 (37.8)
Intraoperative blood loss, n (%)
< 500 mL	49 (50.0)
≥ 500 mL	47 (48.0)
Requirement of blood transfusion, n (%)
No	79 (80.6)
Yes	19 (19.4)

CEA: Carcinoembryonic antigen; IQR: Interquartile range; LN: Lymph node.

Table 2 Univariate analysis of factors associated with overall survival

Variable	HR	95%CI	P value
Age	1.015	0.984-1.047	0.350
Sex
Male	Ref
Female	1.259	0.733-1.162	0.405
Location of primary tumor
Rectum	Ref
Right	1.542	0.780-3.048	0.213
Left	1.370	0.737-2.545	0.319
Regional LN metastasis
No	Ref
Yes	1.444	0.836-2.492	0.187
Time of diagnosis of liver metastasis, %
Synchronous	Ref
Metachronous
Disease-free interval < 12 mo	0.814	0.317-2.094	0.670
Disease-free interval ≥ 12 mo	0.750	0.416-1.352	0.338
Synchronous extrahepatic metastasis
No	Ref
Yes	1.884	0.253-14.0	0.536
Preoperative CEA level
< 200 ng/mL	Ref
≥ 200 ng/mL	1.104	0.392-3.111	0.851
Systemic chemotherapy before liver resection
No	Ref
Yes	1.104	0.439-2.776	0.833
Number of liver metastases
< 5 lesions	Ref
≥ 5 lesions	2.506	1.124-5.585	0.025a
Size of the largest liver lesion
< 4 cm	Ref
≥ 4 cm	1.645	0.934-2.896	0.085
Surgical margin
Clear	Ref
Involved	0.965	0.509-1.829	0.912
Concurrent ablation
No	Ref
Yes	1.449	0.573-3.663	0.434
Operative approach
Laparoscopic	Ref
Open	1.069	0.624-1.832	0.808
Intraoperative blood loss, %
< 500 mL	Ref
≥ 500 mL	1.845	0.985-3.457	0.056
Requirement of blood transfusion, %
No	Ref
Yes	1.326	0.712-2.472	0.374

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

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.

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.

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.

Table 6 Risk score

Factor	Score1
Number of liver metastases ≥ 5	1
Size of liver metastasis ≥ 4 cm	1
Presence of lymph node metastasis in the primary tumor	1

¹Score: 0-1, low risk; 2, moderate risk; 3, high risk. Total risk score is the sum of all scores.