Efficacy and safety of immune checkpoint inhibitors in elderly patients with primary liver cancer: a retrospective, multicenter, real-world cohort study.

BACKGROUND: There is still no specific real-world data regarding the clinical activity of immune checkpoint inhibitors in the elderly with liver cancer. Our study aimed to compare the efficacy and safety of immune checkpoint inhibitors between patients aged ≥ 65 years and the younger group, while exploring their differences in genomic background and tumor microenvironment. METHODS: This retrospective study was conducted at two hospitals in China and included 540 patients treated with immune checkpoint inhibitors for primary liver cancer between January 2018 and December 2021. Patients' medical records were reviewed for clinical and radiological data and oncologic outcomes. The genomic and clinical data of patients with primary liver cancer were extracted and analyzed from TCGA-LIHC, GSE14520, and GSE140901 datasets. RESULTS: Ninety-two patients were classified as elderly and showed better progression-free survival (P = 0.027) and disease control rate (P = 0.014). No difference was observed in overall survival (P = 0.69) or objective response rate (P = 0.423) between the two age groups. No significant difference was reported concerning the number (P = 0.824) and severity (P = 0.421) of adverse events. The enrichment analyses indicated that the elderly group was linked to lower expression of oncogenic pathways, such as PI3K-Akt, Wnt, and IL-17. The elderly had a higher tumor mutation burden than younger patients. CONCLUSIONS: Our results indicated that immune checkpoint inhibitors might exhibit better efficacy in the elderly with primary liver cancer, with no increased adverse events. Differences in genomic characteristics and tumor mutation burden may partially explain these results.