Pretreatment Positron Emission Tomography with (18)F-Fluorodeoxyglucose May Be a Useful New Predictor of Early Progressive Disease following Atezolizumab plus Bevacizumab in Patients with Unresectable Hepatocellular Carcinoma

Background and Aims: The aim of this study was to identify the utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) as a predictor of early progressive disease (e-PD) in patients with hepatocellular carcinoma (HCC) treated with atezolizumab plus bevacizumab (Atezo/Bev). Methods: Twenty consecutive patients with measurable intrahepatic target nodules who received Atezo/Bev treatment were reviewed. The oncological aggressiveness of tumors estimated by 18F-FDG-PET/CT was analyzed using the rate of e-PD within 12 weeks and early progression-free survival (e-PFS) and overall survival (OS). Multivariate analysis was used to identify potential confounders for PD during Atezo/Bev therapy. Results: Using the Response Evaluation Criteria in Solid Tumors version 1.1, a tumor-to-normal liver ratio (TLR) ≥2, indicating higher oncological aggressiveness in HCCs, was associated with lower objective response rates compared with TLR values p = 0.021). In multivariate analysis, TLR ≥2 showed marginal significance as a predictor of e-PD (p = 0.053), and utility as a predictor for worse e-PFS (hazard ratio, 7.153; 95% confidence interval, 1.258–40.689; p = 0.027). In contrast, no significant differences in OS with/without e-PD were observed during the treatment course. In this study, 8 patients experienced e-PD and almost 40% of patients experienced acceptable disease control following subsequent lenvatinib treatment. Conclusion: Pretreatment 18F-FDG-PET/CT may be a useful new predictor of e-PD and may enable early decision-making based on early treatment changes following Atezo/Bev treatment of HCC.