Microwave ablation of colorectal liver metastases: Impact of a 10-mm safety margin on local recurrence in a tertiary care hospital

Abstract

How-I-Do-ItMicrowave ablation (MWA) for colorectal liver metastasis (CLM) has been traditionally considered inferior to surgery due to the higher rate of local recurrence. The study investigated whether a safety margin of 10 mm can improve local control in patients undergoing surgical MWA. Surgical MWA was used to treat 53 lesions in 22 patients with CLM at our Institution from June 2012 to June 2017. The patients' mean age was 64.5 years, and the median size of the lesion was 16.5 mm (9-34 mm). MWA was associated with liver resection in 16 patients (72.7%). The median follow-up was 32.4 months. Univariate and multivariate analyses were performed to identify factors associated with tumor recurrence. Median ablation area was 36.6 mm 2 (30-50 mm 2 ). The complication rate was 22.7%. No local recurrence was observed during follow-up. Disease-free survival was 20 months (4.8-55.2 months). Univariate analysis revealed that the number of liver metastases and node-positive primary tumors were associated with tumor recurrence. Multivariate analysis revealed that node-positive primary tumor was the only factor significantly associated with tumor recurrence (p = 0.049; odds ratio, 12; 95% confidence interval, 1-143). When performed with a 10-mm safety margin, surgical MWA can lead to acceptable oncological outcomes with low morbidity. Therefore, it represents a good option in selected patients with CLM.

An Analysis of Microwave Ablation Parameters for Treatment of Liver Tumors from the 3D-IRCADb-01 Database

“…The success rate for eliminating small liver tumors in patients treated with MWA is greater than 85% [ 30 ]. MWA is also used for the treatment of liver metastases from colorectal cancer [ 31 ].…”

Incremental High Power Radiofrequency Ablation with Multi-electrodes for Small Hepatocellular Carcinoma: A Prospective Study

“…Several studies have shown that the size of the ablative margin affects the development of local tumor progression (LTP) after ablation, with a 0.5-1.0 cm margin typically targeted for liver tumor ablation [5][6][7][8]. Recent studies indicate that achieving a larger ablative margin (greater than 1.0 cm) through MWA may signi cantly reduce the likelihood of LTP [9]. This bene t is associated with the advantages of MWA over RFA, which include its capacity for rapid heating, achieving higher temperatures, and a reduced heat sink effect [9,10].…”

“…Recent studies indicate that achieving a larger ablative margin (greater than 1.0 cm) through MWA may signi cantly reduce the likelihood of LTP [9]. This bene t is associated with the advantages of MWA over RFA, which include its capacity for rapid heating, achieving higher temperatures, and a reduced heat sink effect [9,10]. However, given that most RFA devices currently in use are equipped with a single generator that has a maximum power output of 200 to 250 W, this limitation could notably hinder their capacity to create a su cient safety margin.…”

Anatomical ablation for small hepatocellular carcinomas using multiple applicators: a preliminary study

“…With several studies reporting that the development of LTP after ablation is affected by the size of the ablative margin, a 0.5–1.0 cm ablative margin has generally been pursued for liver tumor ablation [ 9 – 12 ]. Recent studies have also demonstrated that the creation of a large ablative margin greater than 1.0 cm using MWA may help further reduce LTP [ 13 , 14 ]. Regardless of the ablative margin, however, it is generally accepted that percutaneous ablation using the conventional tumor puncture technique has inherent limitations in controlling microscopic metastases originating from the primary tumor through microscopic vascular invasion compared with surgical resection [ 15 , 16 ].…”