Adjuvant immune checkpoint inhibitors after curative HCC treatment associated with reduced recurrence risk

This systematic review and meta-analysis examined the efficacy of adjuvant immune checkpoint inhibitor (ICI)-based therapies versus surveillance in patients with hepatocellular carcinoma (HCC) who had undergone curative treatment. The analysis included 3,478 patients from multiple studies, all of whom had received either resection or ablation as curative treatment for HCC. The setting was specifically the adjuvant phase following these curative procedures, with the goal of preventing recurrence. The population consisted exclusively of patients with HCC who were eligible for adjuvant therapy consideration after achieving a curative-intent outcome.

The intervention evaluated was adjuvant ICI-based treatment, which included both ICI monotherapy and combination regimens with tyrosine kinase inhibitors (TKIs) or anti-angiogenic agents. The comparator was surveillance, representing standard care without active adjuvant pharmacological intervention. Specific dosing protocols, treatment durations, and the exact agents used within the ICI, TKI, and anti-angiogenic classes were not reported in the meta-analysis summary. The analysis compared these active adjuvant strategies against passive monitoring.

For the primary outcome of recurrence-free survival (RFS), adjuvant ICI-based treatment showed significant benefit. The hazard ratio for all ICI-based adjuvant treatments was 0.51 (95% CI: 0.44-0.60, p < 0.001). When analyzed by regimen type, ICI monotherapy demonstrated a hazard ratio of 0.46 (95% CI: 0.35-0.60, p < 0.001), while ICI-TKI/anti-angiogenic combination therapy showed a hazard ratio of 0.55 (95% CI: 0.45-0.68, p < 0.001). Absolute recurrence rates and median RFS times were not reported. The analysis found no statistically significant difference in RFS benefit between monotherapy and combination approaches (p = 0.29).

For the key secondary outcome of overall survival (OS), adjuvant ICI-based therapies also showed improvement. The hazard ratio was 0.51 (95% CI: 0.40-0.65, p < 0.001). As with RFS, absolute survival numbers, median OS times, and survival rates at specific timepoints were not reported. The consistency of benefit across both survival endpoints suggests a potentially meaningful treatment effect, though the magnitude of absolute benefit remains unclear without specific event rates or median differences.

Safety and tolerability findings were notably absent from the reported results. The meta-analysis did not provide data on adverse event rates, serious adverse events, treatment discontinuations due to toxicity, or comparative tolerability profiles between ICI monotherapy and combination regimens. This represents a significant gap in the evidence, as safety considerations are crucial when evaluating adjuvant therapies where patients may be asymptomatic post-curative treatment.

These results contribute to an evolving evidence base for adjuvant therapy in HCC. Prior landmark studies in this area have been limited, with traditional approaches showing modest benefit. The reported hazard ratios of approximately 0.5 for both RFS and OS suggest a potentially stronger treatment effect than seen with some historical adjuvant approaches, though direct comparisons are challenging due to differing patient populations and study designs. The finding that combination therapy did not significantly outperform monotherapy differs from some advanced HCC settings where combinations have shown superiority.

Key methodological limitations include the observational nature of the included studies, which introduces potential confounding and selection bias. The territoriality of included studies may limit generalizability across different global populations with varying HCC etiologies and healthcare systems. The meta-analysis did not report follow-up duration, which is particularly important for assessing durability of adjuvant benefit. Additionally, the lack of safety data and absolute outcome measures limits clinical interpretability.

Clinical implications must be considered cautiously. While the hazard ratios suggest potential benefit, these findings come from observational data and require validation in randomized controlled trials before changing practice. Clinicians should recognize that safety profiles remain undefined for these adjuvant approaches. The decision to use adjuvant ICI-based therapy should currently be made in the context of clinical trials or with careful consideration of individual patient risk factors until more robust evidence emerges.

Several important questions remain unanswered. The optimal patient selection criteria for adjuvant ICI therapy are unclear, as are predictors of response. The comparative efficacy of specific ICI agents and combination partners needs clarification. Long-term outcomes beyond the reported follow-up period are unknown, including late recurrences and potential long-term toxicities. The cost-effectiveness of these approaches in the adjuvant setting has not been evaluated. Most importantly, the safety trade-offs of adjuvant therapy in potentially cured patients require thorough investigation in prospective trials.