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Comparative Study
. 2018 Feb;29(2):268-275.e1.
doi: 10.1016/j.jvir.2017.08.021. Epub 2017 Dec 6.

Percutaneous Microwave versus Radiofrequency Ablation of Colorectal Liver Metastases: Ablation with Clear Margins (A0) Provides the Best Local Tumor Control

Waleed Shady  1 , Elena N Petre  1 , Kinh Gian Do  2 , Mithat Gonen  3 , Hooman Yarmohammadi  1 , Karen T Brown  1 , Nancy E Kemeny  4 , Michael D'Angelica  5 , Peter T Kingham  5 , Stephen B Solomon  1 , Constantinos T Sofocleous  6
Affiliations
Comparative Study

Percutaneous Microwave versus Radiofrequency Ablation of Colorectal Liver Metastases: Ablation with Clear Margins (A0) Provides the Best Local Tumor Control

Waleed Shady et al. J Vasc Interv Radiol. 2018 Feb.

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 = .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 = 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 = .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 = .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.

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Figures

Figure 1
Figure 1
Kaplan-Meier curves for margin size and peri-vascular tumors in the RF group
Figure 2
Figure 2
Kaplan-Meier curves for margin size (significant predictor) and peri-vascular tumors (non-significant predictor) in the MW group.
Figure 2
Figure 2
Kaplan-Meier curves for margin size (significant predictor) and peri-vascular tumors (non-significant predictor) in the MW group.
Figure 3
Figure 3
Kaplan-Meier and cumulative incidence curves by modality (RF and MW) at each margin size.
Figure 3
Figure 3
Kaplan-Meier and cumulative incidence curves by modality (RF and MW) at each margin size.
Figure 4
Figure 4
Figure 4
Figure 4
See this image and copyright information in PMC

References

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