Supplementary Material for: Treatment duration of adjuvant immune checkpoint inhibitors in hepatocellular carcinoma patients at high risk of recurrence after resection: A prospective, multicentric cohort study

Introduction: Adjuvant immune checkpoint inhibitors (ICIs) may improve recurrence-free survival (RFS) in patients with hepatocellular carcinoma (HCC). This study evaluated the effects of adjuvant ICI treatment duration on RFS and overall survival (OS) among patients with HCC at high risk of recurrence.
Methods: The RFS and OS of patients from three centers who received either adjuvant ICI therapy or active surveillance after curative hepatic resection between January 1, 2019 and December 31, 2023 were analyzed. Further analysis was performed to evaluate the effects of ICI treatment duration on RFS and OS.
Results: A total of 1271 patients were included, of whom 1032 (81.2%) received active surveillance and 239 (18.8%) received adjuvant ICI therapy. The median RFS in the adjuvant therapy cohort was 22.6 months (95% CI 18.3–26.9), significantly higher than the RFS of 19.1 months (95% CI 16.4–21.4) in the active surveillance cohort (HR 0.79; 95% CI 0.66–0.95; p = 0.019). The median OS was not reached for either group, but OS tended to be better in the adjuvant therapy cohort than in the active surveillance group (HR 0.72, 95%CI 0.54–0.94; p = 0.010). Similar results were obtained after propensity score matching. Among patients who received adjuvant ICI therapy, those who received it for longer than 6 months had slightly higher RFS (HR 0.66; 95% CI 0.42–1.04; p = 0.071) and OS (HR 0.59; 95% CI 0.30–1.17; p = 0.128) than those who received it for up to 6 months.
Conclusions: Adjuvant ICI therapy significantly improves the prognosis of patients with HCC at high risk of recurrence after curative resection. Six months of adjuvant ICI treatment may be insufficient.