Etiology of Hepatocellular Carcinoma May Influence the Pattern of Progression under Atezolizumab-Bevacizumab

Background: Preclinical models have shown that metabolic dysfunction-associated steatotic liver disease (MASLD)- related hepatocellular carcinoma (HCC) may exhibit reduced responsiveness to immunotherapy, especially for intrahepatic lesions due to liver tumor microenvironment. Radiological pattern of progression has been validated in clinical studies as a useful tool for predicting outcomes in HCC undergoing systemic treatments. Aims: The aim of this study was to determine whether MASLD influences the pattern of progression in patients treated with atezolizumabbevacizumab. Methods: This multicenter, prospective study included patients with unresectable HCC receiving atezolizumab-bevacizumab. Progression patterns were defined as previously proposed. Patients were categorized as either MASLD or controls based on a recent multisocietal Delphi consensus statement. Multivariable models analyzed the risk of specific progression patterns and their impacts on post-progression survival (PPS) and overall survival (OS). A historical cohort treated with sorafenib was also analyzed to determine whether observed patterns were specific for atezolizumab-bevacizumab. Results: Four-hundred twenty patients were included (MASLD: n = 88, 21.0%). Time to progression (TTP) was shorter in MASLD compared to controls, due to an increased risk of intrahepatic growth (IHG - hazard ratio [HR] 1.739, 95% confidence interval [CI] 1.206-2.507, p = 0.003]). Neither etiology nor IHG predicted a different PPS. No differences between etiologies were found in OS. Etiology did not influence the pattern of progression under sorafenib in the historical cohort. Conclusion: IHG was more frequently associated with MASLD-HCC compared to controls, confirming preclinical data and suggesting biological differences between tumors, with potential implications for future research. MASLD should not be seen as a contraindication to immunotherapy.