Development of a prognostic score to predict response to Yttrium-90 radioembolization for hepatocellular carcinoma with portal vein invasion

Background & aims: Yttrium-90 transarterial radioembolization (TARE) has shown promising efficacy in the treatment of patients with hepatocellular carcinoma (HCC), associated with portal vein tumor thrombus (PVTT). The aim of this study is to identify prognostic factors for survival in patients with HCC and PVTT undergoing TARE, and build a prognostic classification for these patients.

Methods: This is a single center retrospective study conducted over six years (2010-2015), on consecutive patients undergoing TARE. Patients were included if they met the following criteria: presence of at least one measurable HCC, presence of PVTT not occluding the main portal trunk, absence of extrahepatic metastases, Child-Pugh score within B7, Eastern Cooperative Oncology Group performance status 0-1. Uni- and multivariable analysis was used to explore the variables that showed an independent relationship with survival. A prognostic score was then derived, and three prognostic categories were identified.

Results: A total of 120 patients were included in the study. Median overall survival (OS) was 14.1 months (95% CI 10.7-17.5) and median progression-free survival (PFS) was 6.5 months (95% CI 3.8-9.2). The only variables independently correlated with OS were bilirubin, extension of PVTT and tumor burden. Three prognostic categories were identified: favourable prognosis (0 points), intermediate prognosis (2-3 points) and dismal prognosis (>3 points). Median OS in the three categories was 32.2 months, 14.9 months and 7.8 months respectively (p <0.0001). PFS (p = 0.045) and the risk of liver decompensation (p <0.0001) also significantly differed along the same prognostic categories.

Conclusions: Radioembolization with Yttrium-90 is an effective therapy for patients with HCC and PVTT. The proposed prognostic stratification may help to better identify good candidates for the treatment, and those for whom TARE may be futile.

Lay summary: Yttrium-90 transarterial radioembolization (TARE) is a microembolic procedure that minimizes alterations to hepatic arterial flow, and thus can be safely performed in patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus (PVTT). In this study, we retrospectively evaluated the independent predictors of long-term outcomes in patients with HCC and PVTT treated with TARE. Bilirubin level, extension of PVTT and tumor burden were independently related to post-treatment survival: the combination of these factors allowed us to build a prognostic stratification that may help to better identify good candidates for the treatment, and those for whom TARE may be futile.