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

SIMPLE SUMMARY: Microwave (MW) ablation is increasingly used worldwide as a therapeutic option in very-early- and early-stage hepatocellular carcinoma (HCC). Up to now, there have been few published studied showing the correlation with pathology in ablated nodules. The aim of our study was to retrospectively correlate the necrosis obtained with MW ablation with histological findings in excised livers from the time of liver transplantation to assess the MW ablation effectiveness. We obtained, in a population of 30 patients with 36 nodules, a complete ablation at 1-month imaging in 30/36 nodules (83.3%). At pathology, of the 36 treated nodules, 28 (77.8%) showed complete necrosis, and 8 (22.2%) showed partial necrosis. Good agreement was found between the imaging performed 1-month after treatment and the complete pathological response. These data confirm the effectiveness of MW ablation to percutaneously treat HCC nodules smaller than 3 cm with a high sensitiveness of radiological imaging in detecting a complete response after ablation. 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.