Microwave Ablation of Very-Early- and Early-Stage HCC: Efficacy Evaluation by Correlation with Histology after Liver Transplantation

Abstract

Microwave (MW) ablation is a worldwide-diffused technique for the percutaneous ablation of hepatocellular carcinoma (HCC). Nevertheless, the efficacy of this technique still needs to be confirmed in pathological specimens. The purpose of this study was to evaluate the efficacy of MW ablation by correlation with histology in excised liver samples at the time of liver transplantation (LT). All patients with MW-ablated HCC who subsequently underwent LT between 2012 and 2020 were retrospectively evaluated. In the explanted livers, the treated lesions were evaluated at pathology, and the necrosis was classified as complete or partial. Thirty-six HCCs were ablated in 30 patients (20.9 ± 6.1 mm, a range of 10–30 mm). Ablations were performed with a single insertion of a MW antenna under ultrasound or CT guidance. A complete radiological response was demonstrated in 30/36 nodules (83.3%) in 24/30 patients (80%) at imaging performed one-month after MW ablation. At pathology, of the 36 treated nodules, 28 (77.8%) showed a complete necrosis, and 8 (22.2%) showed a pathological partial necrosis. Good agreement was found between the imaging performed one-month after treatment and the complete pathological response (Cohen’s k = 0.65). The imaging accuracy in detecting a complete response to treatment was 88.9%. All lesions with complete necrosis did not show recurrence at follow-up imaging until transplantation. The rad-path correlation in the explanted livers showed that MW ablation achieved a high rate of complete necrosis if a macroscopical complete ablation was obtained.

Locoregional Treatments for Bridging and Downstaging HCC to Liver Transplantation

“…In a recent retrospective study including 40 HCC nodules percutaneously treated with MWA in patients who subsequently underwent LT, complete and partial necrosis were found in 77.8% and 22.2% of cases, respectively, at the excised liver after LT [ 45 ]. These results were obtained with a single MWA session, whereas often in RFA series the treatment is applied two, or even three, times [ 36 , 37 , 45 ].…”

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

“…MWA is a widely used thermal ablation modality for eradicating malignant cells with minimal damage to the surrounding tissues [ 32 , 33 , 34 ]. It consists in focusing an energy source in the target zone (the tumoral tissue) causing tumor destruction.…”

Hepatocellular carcinoma downstaging for liver transplantation in the era of systemic combined therapy with anti‐VEGF/TKI and immunotherapy

“…Rather, multiple studies have demonstrated that percutaneous ultrasound and/or CT‐guided radiofrequency (RFA) or microwave are safe and effective for bridging to transplant with high rate of complete pathologic necrosis (>75%) either (1) after initial downstaging with TACE to within Milan criteria or (2) for patients initially within Milan criteria with very early or early stage HCC. [ 35–40 ] However, for HCC >2–3 cm and/or located near large blood vessels, rates of complete pathologic necrosis after ablation with standard imaging and guidance techniques have historically been lower (30%–55%). [ 38 ] Nonetheless, Bale et al [ 41 ] performed an important study examining percutaneous stereotactic radiofrequency ablation as bridging therapy to transplant in 97 patients with 195 HCC nodules (median tumor size was 2.5 cm; range, 1–8 cm).…”