[DJR-120 1.0 CE] Percutaneous Microwave Versus Radiofrequency Ablation of Colorectal Liver Metastases: Ablation with Clear Margins (A0) Provides the Best Local Tumor Control

Click on the file under “Materials” to download the PDF from the Journal of Vascular and Interventional Radiology. Read the text and then complete the quiz below.

ABSTRACT
Purpose: To identify and compare predictors of local tumor progression (LTP)-free survival (LTPFS) after radiofrequency (RF) ablation and microwave (MW) ablation of colorectal liver metastases (CLMs).

Materials and Methods: This is a retrospective review of CLMs ablated from November 2009 to April 2015 (110 patients). Margins were measured on contrast-enhanced computed tomography (CT) 6 weeks after ablation. Clinical and technical predictors of LTPFS were assessed using a competing risk model adjusted for clustering.

Results: Technique effectiveness (complete ablation) was 93% (79/85) for RF ablation and 97% (58/60) for MW ablation (P 1⁄4 .47). The median follow-up period was significantly longer for RF ablation than for MW ablation (56 months vs. 29 months) (P < .001). There was no difference in the local tumor progression (LTP) rates between RF ablation and MW ablation (P 1⁄4 0.84). Significant predictors of shorter LTPFS for RF ablation on univariate analysis were ablation margins 5 mm or smaller (P < .001) (hazard ratio [HR]: 14.6; 95% confidence interval [CI]: 5.2–40.9) and perivascular tumors (P 1⁄4 .021) (HR: 2.2; 95% CI: 1.1–4.3); both retained significance on multivariate analysis. Significant predictors of shorter LTPFS on univariate analysis for MW ablation were ablation margins 5 mm or smaller (P < .001) (subhazard ratio: 11.6; 95% CI: 3.1–42.7) and no history of prior liver resection (P < .013) (HR: 3.2; 95%: 1.3–7.8); both retained significance on multivariate analysis. There was no LTP for tumors ablated with margins over 10 mm (median LTPFS: not reached). Perivascular tumors were not predictive for MW ablation (P 1⁄4 .43).

Conclusions: Regardless of the thermal ablation modality used, margins larger than 5 mm are critical for local tumor control, with no LTP noted for margins over 10 mm. Unlike RF ablation, the efficiency of MW ablation was not affected for perivascular tumors. 

STRUCTURED EDUCATION:

RA – 2017 Procedures Abdominal Section 0.50

RA – 2018 Procedures Abdominal Section 0.50

VI – 2016 Procedures Abdominal Angiography and Intervention, GU and GI Nonvascular Procedures 1.00

VI – 2017 Procedures Nonvascular Procedures 1.00