Table 2.

Univariate and multivariate analyses for local tumor progression-free survival

	N	Local tumor progression-free survival rate, %*		Univariate P value†	Hazard ratio (95% CI)	Multivariate P value‡
		1 year	3 years
All patients	82	85	58	-	-	-
Sex§
F	28	75	42	0.053	1.18 (0.52–2.60)	0.693
M	54	90	67
Age, years
≥60	39	85	58	0.851	-	-
<60	43	85	57
Primary tumor location
Colon	68	82	60	0.550	-	-
Rectum	14	100	51
Primary tumor origin
Midgut	16	59	37	0.249	-	-
Hindgut	66	91	63
Primary tumor lymph node metastasis
Yes	58	88	64	0.320	-	-
No	24	79	47
History of hepatic resection§
No	33	75	34	<0.001	2.35 (1.02–5.45)	0.045
Yes	49	92	73
Pre-ablation chemotherapy
Yes	54	85	49	0.157	-	-
No	28	86	78
Pre-ablation chemotherapy cycles§
>6	30	79	49	0.073	1.78 (0.81–3.89)	0.150
≤6 or no chemotherapy	52	88	63
Fluorouracil-based chemotherapy regimen
Oxaliplatin
Yes	30	86	46	0.250	-	-
No	52	84	68
Irinotecan
Yes	25	83	46	0.237	-	-
No	57	86	63
Use of bevacizumab
Yes	33	81	43	0.159	-	-
No	49	87	70
Use of anti-EGFR agent
Yes	8	75	75	0.229	-	-
No	74	86	57
Time between CLM discovery and ablation, days§
>120	46	85	51	0.074	1.35 (0.57–3.05)	0.490
≤120	36	85	66
Ablation modality
RFA	45	89	61	0.320	-	-
Microwave or cryoablation	37	80	54
Minimal radiographic ablation margin, mm§
<5	30	80	38	0.028	2.40 (1.18–4.87)	0.016
≥5	52	88	69
CLM location
Subcapsular	43	79	53	0.240	-	-
Non-subcapsular	39	92	64
CEA level at ablation, ng/mL
≥5	36	78	55	0.472	-	-
<5	46	93	60
Maximum CLM diameter at ablation, cm§
≥2	32	81	47	0.009	1.90 (0.94–3.91)	0.072
<2	50	88	66
Number of CLM
Solitary	70	88	60	0.376	-	-
Multiple	12	67	46
Concomitant extrahepatic metastases
Presence	19	95	42	0.119	-	-
Absence	63	82	65
RAS status §
Mutant	29	67	26	<0.001	2.65 (1.18–5.94)	0.019
Wild-type	53	94	74
Post-ablation chemotherapy
Yes	43	83	57	0.701	-	-
No	39	87	60

^*Kaplan-Meier analysis.

^†Log-rank test.

^‡Cox regression model.

^§Variables entered into the Cox regression model.

EGFR, epidermal growth factor receptor; CLM, colorectal liver metastases; RFA, radiofrequency ablation; CEA, carcinoembryonic antigen.