Effect of Subgroups on Study Outcomes in Unresectable Hepatocellular Carcinoma Undergoing Upfront Systemic Treatment: A Meta-analysis.

Objectives: Immunotherapy improved the outcome of patients with unresectable hepatocellular carcinoma, but not all studies are in agreement, nor is it clear whether certain subgroups have really benefited. This study aims to perform an updated meta-analysis of trials comparing upfront immunotherapy-based regimens versus tyrosin-kinase inhibitors, and some exploratory analyses.

Methods: After a systematic review, randomized trials of immunotherapy-based regimens versus tyrosin-kinase inhibitors were selected. A meta-analysis assessed the relationship between treatment arm and overall survival. Based on the resulting heterogeneity, a further investigation of 11 variables by meta-regression and an exploration of subgroups were planned.

Results: Eight studies were selected. From the meta-analysis, the overall survival improvement for the immunotherapy-based arms was consistent (HR: 0.77, CI: 0.68-0.88), although heterogeneity between studies was significant ( Q =16.37; P =0.0373; I2 =51.1%). After meta-regression, the effect of the experimental arm was more pronounced in the elderly and lost among patients with HCV-related liver disease. Subgroups suggested a favorable effect of immunotherapy in patients with HBV-related hepatocellular carcinoma, extrahepatic dissemination, and elevated alpha-fetoprotein.

Conclusion: The study results confirm the significant overall survival improvement after immunotherapy-based regimens but suggest different effects on the outcome depending on age, etiology of liver disease, and tumor burden.