Liver-Directed Combined Radiotherapy for Downstaging of the Milan Advanced Hepatocellular Carcinoma Converting to Liver Transplantation

Abstract

Recent success of combined immunotherapy sheds a light to the future of advanced hepatocellular carcinoma patients but still remains as a palliative setting. The best oncologic outcome for HCC can be obtained by curative surgery either by resection or liver transplantation (LT). Efficacy of liver-directed combined radiotherapy (LD-CRT) for downstaging and subsequent surgical resection in locally advanced HCC had been reported earlier by our team. In this study, we investigated the role of LD-CRT as a downstaging strategy for converting advanced hepatocellular carcinoma to LT. We reviewed 55 hepatocellular carcinoma patients who had undergone downstaging LD-CRT and subsequent liver transplantation from January 2009 to February 2022. Patients within Milan criteria at the time of receiving radiotherapy were excluded and clinical characteristics and histopathology of explant liver were evaluated. The overall survival and disease-free survival were assessed using the Kaplan-Meier method RESULTS: The median follow-up period was 48.6 months (range 6.9 - 151.7 months). Of 55 patients, 24 (43.6%) were treatment naïve. At the time of RT, 36 patients presented large tumor (tumor diameter >5 cm) or multiple lesions (>3 lesions), 37 with major vessel involvement or portal vein tumor thrombosis, and 7 with extrahepatic lesion. LD-CRT was given as localized concurrent chemoradiation (CCRT) for 41 patients (74.5%) and transarterial chemoembolization (TACE) plus RT for 10 patents (18.2%). Substantial downstaging has been achieved in 38 (69%) patients with initially over the Milan to within Milan. Specifically, 29 of 37 patients initially with major vessel invasion or with tumor thrombosis were successfully converted to microscopic vessel invasion or tumor thrombus-free status in explant liver. 5-year overall survival was 68.1% and 2-year disease-free survival was 51%, respectively. Recurrence after transplantation was observed in 18 patients (4 intrahepatic recurrence and 14 extrahepatic metastasis) and the majority (14/18) occurred within 2 years. Liver-directed combined radiotherapy as a downstaging strategy for liver transplantation achieved favorable oncologic outcomes in advanced hepatocellular carcinoma patients. This study suggests that active adoption of radiotherapy needs full consideration for locally advanced HCC patients, opening a chance for curative LT.