Portal vein tumor thrombus radiotherapy improves the outcomes of immunotherapy plus bevacizumab in hepatocellular carcinoma: A multicenter real-world research of southwest China

Abstract Background: The aim of this study was to investigate the changes in some immune-related indicators after radiotherapy for portal vein tumor thrombosis (PVTT) in patients with hepatocellular carcinoma (HCC), to evaluate the efficacy and safety of sequential immune checkpoint inhibitors (ICIs) plus bevacizumab therapy after radiotherapy for PVTT, and to preliminarily explore the factors affecting the efficacy of patients. Methods: Retrospective data were collected from three hospitals in southwestern China, patients of HCC complicated with PVTT were analyzed, patients were divided into the PVTT radiotherapy combined with ICIs plus bevacizumab group (PVTT radiotherapy group) and ICIs plus bevacizumab group (control group). The difference of progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR) of the two groups were analyzed, and the potential factors affecting PFS were analyzed. The adverse events (AEs) were compared between the two groups. Results: A total of 113 patients were treated with ICIs plus bevacizumab as a first line treatment, of whom 55 patients had been treated with PVTT radiotherapy before first treatment. There were significant differences in some immune-related indicators before and after radiotherapy for PVTT. The patients in PVTT radiotherapy group had a longer PFS (median, 10.1 vs. 5.8 months, P < 0.05), and the PFS rates of 3 months, 6 months, 9 months and 12 months were 98.18% vs. 93.10%, 83.64% vs. 44.83%, 58.18% vs. 6.90% and 23.64% vs. 1.72%, respectively, with statistical differences (P < 0.05). There were no significant difference in ORR (41.82% vs.37.93%, P = 0.704) and DCR (87.27% vs.82.61%, P = 1.000) between the two groups, but the ORR and DCR of the PVTT radiotherapy group were showed a higher results, and no serious AEs were observed. Multivariate Cox analysis showed that the expression of AFP, the gross classification of HCC, PVTT type, extrahepatic metastasis, and PVTT radiotherapy were independent influencing factors of PFS (P < 0.05). Conclusions: Sequential ICIs plus bevacizumab therapy after radiotherapy for PVTT of HCC patients is safe and feasible, which may further prolong the PFS of patients.