Differential effects of the KRAS gene on recurrence in right- vs left-sided colorectal liver metastases undergoing radiofrequency ablation

Table 1 Demographic and clinicopathologic characteristics, n (%)

Characteristics	No. of patients (n = 164)	KRAS
		Wild (n = 89)	Mutation (n = 75)	P value
Age (year), mean	58.0 ± 9.8	57.0 ± 9.5	59.1 ± 10.0	0.167
≤ 60	90 (54.9)	51 (56.7)	39 (43.3)	0.497
> 60	74 (45.1)	38 (51.4)	36 (48.6)
Sex				0.794
Male	98 (59.8)	54 (55.1)	44 (44.9)
Female	66 (40.2)	35 (53.0)	31 (47.0)
Primary tumor site				0.017
Right colon	27 (16.5)	9 (33.3)	18 (66.7)
Left colon	137 (83.5)	80 (58.4)	57 (41.6)
Primary tumor invasion				0.203
T1-2	11 (6.7)	8 (72.7)	3 (27.3)
T3-4	153 (93.3)	81 (52.9)	72 (47.1)
Nodal status of primary tumor				0.561
Positive	128 (78.0)	71 (55.5)	57 (44.5)
Negative	36 (22.0)	18 (50.0)	18 (50.0)
Time of CLM				0.504
Synchronous	85 (51.8)	44 (51.8)	41 (48.2)
Heterochronous	79 (48.2)	45 (57.0)	34 (43.0)
Extrahepatic metastases				0.139
Yes	75 (45.7)	36 (48.0)	39 (52.0)
No	89 (54.3)	53 (59.6)	36 (40.4)
Tumor size (cm)
Median diameter, cm (quartile)	2.2 (1.7-2.9)	2.0 (1.7-2.7)	2.2 (1.6-3.3)	0.236
≤ 3	123 (75.0)	71 (57.8)	52 (42.2)	0.124
> 3	41 (25.0)	18 (43.9)	23 (56.1)
DFI (months)				0.485
< 12	137 (83.5)	76 (55.5)	61 (44.5)
≥ 12	27 (16.5)	13 (48.1)	14 (51.9)
CEA level (ng/mL)				0.914
≤ 30	135 (82.3)	73 (54.1)	62 (45.9)
> 30	29 (17.7)	16 (55.2)	13 (44.8)
CRS				0.313
0-2	77 (47.0)	45 (58.4)	32 (41.6)
3-5	87 (53.0)	44 (50.6)	43 (49.4)
Liver metastases resection pre-RFA				0.485
Yes	66 (40.2)	38 (57.6)	28 (42.4)
No	98 (59.8)	51 (52.0)	47 (48.0)
Preoperative chemotherapy				0.221
Yes	148 (90.2)	78 (52.7)	70 (47.3)
No	16 (9.8)	11 (68.8)	5 (31.2)
Ablative margin (mm)				0.156
< 5	17 (10.4)	7 (41.2)	10 (58.8)
5-10	101 (61.6)	52 (51.5)	49 (48.5)
> 10	46 (28.0)	30 (65.2)	16 (34.8)

DFI: Disease-free interval from primary resection to the diagnosis of liver metastasis; CRS: Node-positive primary tumor, DFI < 12 months, more than one liver tumor, size of largest tumor > 3 cm, carcinoembryonic antigen level > 30 ng/mL (mg/L); RFA: Radiofrequency ablation; CLM: Colorectal liver metastases; CEA: Carcinoembryonic antigen.