Predictive factors and survival outcome of conversion therapy for unresectable hepatocellular carcinoma patients receiving atezolizumab and bevacizumab: Comparative analysis of conversion, partial response and complete response cases.

Abstract Aim This study aims to investigate the predictive factors for conversion therapy in patients with unresectable hepatocellular carcinoma (uHCC) and to evaluate the prognosis of conversion cases by comparing them with partial response (PR) and complete response (CR) cases. Methods In this retrospective multicenter study, we included a total of 946 uHCC patients treated with atezolizumab and bevacizumab (Atez/Bev) from September 2020 to September 2023. Results Out of the patients, 43 (4.5%) received conversion therapy following Atez/Bev treatment. The overall response rate was 65.1% and 23.7% in the conversion and non-conversion group, with a statistical significance (p < 0.001). Multivariate analyses show that BCLC stage B or an earlier stage (p = 0.045), absence of macrovascular invasion and extrahepatic spread (p = 0.045), and a low value of neutrophil to lymphocyte ratio (p = 0.04) were significantly favorable predictive factors associated with conversion therapy. The conversion group showed significantly better survival compared to the non-conversion group (p < 0.001). In the landmark analysis at 6, 12, and 18 months, the conversion group exhibited better survival compared to PR patients in the non-conversion group (p = 0.04, 0.01, and 0.03, respectively) and there were no significant differences in the overall survival (OS) between the conversion group and achieving CR cases (p = 0.7, 1.0, and 0.3, respectively) Conclusions Patients with low tumor burden and low value of NLR were more likely to undergo conversion therapy. The OS of patients undergoing conversion therapy showed better survival compared to those achieving PR and was comparable to those with CR patients. Conversion therapy should be considered if feasible.