The value of KRAS gene status in predicting local tumor progression of colorectal liver metastases following radiofrequency ablation

Figures & data

Figure 1. Patient disposition.

Table 1. Baseline characteristics of patients with colorectal liver metastases.

	No. of patients	KRAS gene status		p Value
		Wild-type	Mutant
Age, years	–	–	–	.358
≤60	36	16	20	–
>60	40	22	18	–
Sex	–	–	–	.231
Female	49	27	22	–
Male	27	11	16	–
Tumor size, cm	–	–	–	.000
≤3	54	27	27	–
>3	22	11	11	–
Primary site of the tumor	–	–	–	.150
Right colon	15	5	10
Left colon	61	33	28
Pathological differentiation of the primary lesion	–	–	–	.773
poorly	15	7	8	–
Moderately or well	61	31	30	–
Depth of invasion				.238
T1–3	29	12	17	–
T4	47	26	21	–
Lymph node at the primary site	–	–	–	.589
Positive	58	28	30	–
Negative	18	10	8	–
Time of liver metastasis				.966
Synchronous	45	22	23
Heterochronous	31	15	16
Extrahepatic metastases	–	–	–	.646
Yes	40	19	21	–
No	36	19	17	–
No. of liver metastases	–	–	–	.185
≤3	57	26	31	–
>3	19	12	7	–
CEA	–	–	–	1.000
≤30	62	31	31
>30	14	17	17	–
History of liver metastasis resection pre-RFA	–	–	–	.629
Yes	26	12	14	–
No	50	26	24	–
Margin, mm	–	–	–	.442
≤5	9	4	5	–
6–10	55	26	29	–
>10	12	8	4	–
CRS	–	–	–	1.000
0–2	30	15	15	–
3–5	46	23	23	–
DFI
<12	16	7	9	–
≧12	60	31	29	–

RFA: radiofrequency ablation; No: number.

Modified CRS: Node-positive primary tumor, DFI <12 months, more than one liver tumor, size of largest tumor >3 cm, CEA level >30 ng/mL (mg/L) (Radiology [11]).

DFI: disease-free interval from primary resection to the diagnosis of liver metastasis.

Figure 2. (a) Local tumor progression and KRAS gene status (p=.011). (b) Local tumor progression and tumor size (p=.002). (c) Local tumor progression and ablation margin size (p<.001). (d) Local tumor progression and CRS (p=.038).

Table 2. Univariate and multivariate analyses for factors affecting local tumor progression.

Variables	No. of tumors	Univariate analyses	Multivariate analyses
		p Value	p Value	Hazard ratio	95% confidence interval
Age
≤60	73	.674	–	–	–
>60 years	81	–	–	–	–
Sex
Male	98	.454	–	–	–
Female	56	–	–	–	–
Tumor size
≤3 cm	121	.002	.697	1.199	0.481–2.985
>3 cm	33	–	–	–	–
Primary site of the tumor
Right colon	21	0.437	–	–	–
Left colon	133	–	–	–	–
Pathological differentiation
Poorly	24	.068	–	–	–
Moderately or well	130	–	–	–	–
Depth of invasion
T1-3	65	.111	–	–	–
T4	89	–	–	–	–
Lymph node status
Positive	114	.917	–	–	–
Negative	40	–	–	–	–
KRAS gene
Wild-type	82	.011	.005	0.309	0.135–0.706
Mutation	72	–	–	–	–
Time of liver metastasis
Synchronous	108	.168	–	–	–
Heterochronous	46	–	–	–	–
Ablative margin (mm)
≤5	18	–	–	–	–
5–10	108	.000	.000	0.180	0.890–0.362
>10	28	–	–	–	–
Extrahepatic metastases
Yes	79	.991	–	–	–
No	75	–	–	–	–
DFI (months)
<12	124	.895	–	–	–
≧12	30	–	–	–	–
CEA
≤30	120	.109	–	–	–
>30	34	–	–	–	–
CRS
0–2	61	.038	.033	2.692	1.084–6.688
3–5	93	–	–	–	–
No. of liver metastases
≤3	98	.689	–	–	–
>3	56	–	–	–	–
History of liver Metastasis resection pre-RFA	–	.583	–	–	–
Yes	49	–	–	–	–
No	105	–	–	–	–

RFA: radiofrequency ablation; No: number.

Modified CRS: Node-positive primary tumor, DFI < 12 months, more than one liver tumor, size of largest tumor >3 cm, CEA level > 30 ng/mL (mg/L) (Radiology [11]).

DFI: disease-free interval from primary resection to the diagnosis of liver metastasis.