On-Demand Loco-Regional Treatment for Intrahepatic Lesions Improves Treatment Outcomes in Atezolizumab Plus Bevacizumab Therapy for Unresectable Hepatocellular Carcinoma

Background/Objectives: Atezolizumab plus bevacizumab (Atez/Bev) is a standard treatment for unresectable hepatocellular carcinoma (HCC), but its anti-tumor efficacy remains limited. Combining intrahepatic locoregional treatment (IHLRT) with Atez/Bev has been explored as a strategy to overcome this limitation. This study aimed to clarify the significance of IHLRT in Atez/Bev treatment for unresectable HCC. Methods: Eighty consecutive patients with unresectable HCC treated with Atez/Bev were retrospectively analyzed. IHLRT was performed in patients with residual viable hepatic lesions amenable to locoregional treatment during Atez/Bev therapy. Anti-tumor response was evaluated by RECIST; and progression-free survival (PFS), overall survival (OS), potential biomarkers, and contributing factors to OS were also assessed. Results: IHLRT was selectively performed in 20 patients based on individual clinical conditions. Pretreatment characteristics were comparable between patients who did and did not receive IHLRT. Both best and initial tumor responses were superior in the IHLRT group, and PFS was significantly longer (16.2 vs. 8.4 months, p = 0.019), with comparable rates of severe treatment-related adverse events. On multivariate analysis, hepatic reserve function, objective response, neutrophil-to-lymphocyte ratio (NLR) and IHLRT were independent predictors of OS (HR: 2.17, 3.13, 0.58, and 1.62; p = 0.02, <0.01, 0.03 and 0.03, respectively). Although high NLR was a negative predictive factor, IHLRT appeared to mitigate the negative prognostic impact of an elevated NLR. Conclusions: On-demand, selective IHLRT during Atez/Bev treatment is well tolerated and provides superior and more durable tumor control, particularly in patients achieving an initial objective response.