Clinico-characteristics of patients which correlated with preferable treatment outcomes in immunotherapy for advanced hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) is the third-most lethal malignant tumor worldwide. The rapid development of immunotherapy utilizing immune checkpoint inhibitors for advanced HCC patients has been witnessed in recent years, along with numerous randomized clinical trials demonstrating the survival benefits for these individuals. This systematic review and meta-analysis aimed to identify specific clinico-pathological characteristics of advanced HCC patients that may lead to preferable responses to immunotherapy in terms of overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). METHODS: The included clinical trials were retrieved from PubMed, Embase, the Cochrane library, and the Web of Science databases published in English between 1 January 2002 and 20 October 2022. A systematic review and meta-analysis for first-line and second-line phase II/III studies were conducted on immunotherapy for patients with advanced HCC by using OS as the primary outcome measure, and PFS and ORR as the secondary outcome measures to obtain clinico-pathological characteristics of patients which might be preferable responses to programmed death-1 (PD-1) and programmed cell death-Ligand 1 (PD-L1) inhibitors. Toxicity and specific treatment-related adverse events (TRAEs) were also determined. RESULTS: After screening 1392 relevant studies, 12 studies were included in this systematic review and meta-analysis to include 5948 patients. Based on the analysis of interaction, the difference in OS after first-line immunotherapy between the subgroups of viral hepatitis [hazard ratio (HR)=0.73 vs 0.87, P for interaction=0.02] and macrovascular invasion and/or extrahepatic spread (HR=0.73 vs 0.89, P for interaction=0.02) were significant. The difference in PFS between the subgroups of viral hepatitis was highly significant (pooled HR=0.55 vs 0.81, P for interaction=0.007). After second-line immunotherapy, the difference in ORR between the subgroups of Barcelona Clinic Liver Cancer was significant (pooled ES=0.12 vs 0.23, P for interaction=0.04). Compared with PD-L1 inhibitors, PD-1 inhibitors may have a higher probability to cause TRAEs. Diarrhea, increased aspartate aminotransferase, and hypertension were the top three TRAEs. CONCLUSIONS: This systematic review and meta-analysis represents the first pilot study aimed at identifying crucial clinico-pathological characteristics of patients with advanced HCC that may predict favorable treatment outcomes in terms of OS, PFS, and ORR to immunotherapy. Findings suggest that patients with viral hepatitis positivity (especially hepatitis B virus) and macrovascular invasion and/or extrahepatic spread may benefit more in OS when treated with PD-1/PD-L1 immune checkpoint inhibitors.