Oncological outcomes and predictors of radiofrequency ablation of colorectal cancer liver metastases

Table 1 Univariate and multivariate analyses for local tumor progression-free survival

Variable	Number of tumors (n = 138)	LTP rate (%)	Univariate	Multivariate
			P value	HR (95%CI)	P value
Gender			0.052
Male	91	27.5
Female	47	42.6
Age (yr)			0.653
≤ 60	76	30.3
> 60	62	35.5
Location of primary tumor			0.868
Colon	99	32.3
Rectum	39	33.3
TNM classification			0.502
I, II, or III	81	30.9
IV	57	35.1
Tumor differentiation			0.591
Well or moderate	81	34.6
Poor	57	29.8
Previous liver resection			0.120
No	105	29.5
Yes	33	42.4
EHD			0.522
No	93	32.3
Yes	45	33.3
Tumor number			0.799
1	45	35.6
2 or 3	93	31.2
Tumor size			< 0.001	3.712 (1.894-7.277)	< 0.001
≤ 3 cm	86	15.1
> 3 to 5 cm	52	61.5
Ablative margin			< 0.001	3.077 (1.479-6.405)	0.003
≤ 5 mm	67	52.2
> 5 mm	71	14.1

LTP: Local tumor progression; LTPFS: Local tumor progression-free survival; EHD: Extrahepatic disease; HR: Hazard ratio; CI: Confidence interval.

Table 2 Univariate and multivariate analyses for overall survival

Variable	Number of patients (n = 85)	Median OS (mo)	Univariate	Multivariate
			P value	HR (95%CI)	P value
Gender			0.341
Male	56	42
Female	29	35
Age (yr)			0.504
≤ 60	44	35
> 60	41	36
Location of primary tumor			0.229
Colon	62	42
Rectum	23	33
TNM classification			0.208
I, II, or III	52	45
IV	33	33
Tumor differentiation			0.100
Well or moderate	56	36
Poor	29	34
Previous liver resection			0.084
No	65	36
Yes	20	34
EHD			< 0.001	3.676 (1.730-7.811)	0.001
No	63	50
Yes	22	26
Tumor number			< 0.001	2.475 (1.099-5.573)	0.029
1	45	50
2 or 3	40	26
Maximum tumor diameter			< 0.001	3.641 (1.732-7.654)	0.001
≤ 3 cm	48	45
> 3 to 5 cm	37	26
Minimum ablative margin			0.367
≤ 5 mm	44	33
> 5 mm	41	36

OS: Overall survival; EHD: Extrahepatic disease; HR: Hazard ratio; CI: Confidence interval.