AbstractBackground and AimsWe aimed to validate the predictive factors for tumor response and the prognostic impact of conversion therapy aimed at cancer‐ and drug‐free states in patients with unresectable hepatocellular carcinoma (u‐HCC) undergoing atezolizumab plus bevacizumab (Atez/Bev) therapy.MethodsThis retrospective study enrolled 156 patients who were Child‐Pugh class A with u‐HCC treated using Atez/Beva. The profile of objective response was investigated using decision‐tree analysis. Progression‐free, recurrence‐free, and overall survival were assessed.ResultsThe progression‐free and overall survival were 6.1 and 18.0 months, respectively. Objective response and disease control rates were 32.0% and 84.0%, respectively. Decision‐tree analysis revealed that neutrophil‐to‐lymphocyte ratio (NLR) <3, modified albumin‐bilirubin grade (m‐ALBI) 1 or 2a, and age < 75 were sequential splitting variables for the objective response, respectively. In the multivariate analysis, NLR <3 and m‐ALBI grade 1 or 2a were identified as predictive factors for objective response. We successfully achieved eligibility for conversion therapy in 17 patients after Atez/Bev therapy significant response. Following conversion therapy, the curative therapy group, including surgical resection or radiofrequency ablation (RFA), had significantly higher recurrence‐free survival than did the transcatheter arterial chemoembolization (TACE) and Atez/Bev discontinuation (surgical resection or RFA; not reached vs. TACE; 5.3 months,p= 0.008, Atez/Bev discontinuation; 3.9 months,p= 0.048, respectively) groups.ConclusionsNLR <3 and m‐ALBI grade 1 or 2a were predictive factors for conversion therapy, leading to cancer‐ and drug‐free states in patients with u‐HCC undergoing Atez/Bev therapy. Moreover, surgery or RFA may be suitable for conversion therapy for cancer‐free status.