To synthesize available data regarding the disease-free survival (DFS) benefit of adjuvant immune checkpoint inhibitors (ICIs) for patients with RCC and evaluate the overall safety profile of ICIs in this setting.
We utilized PubMed, Embase, and relevant conference proceedings to identify phase III randomized controlled trials comparing adjuvant ICI versus placebo/observation for RCC. The primary outcome of interest was DFS. Variables for subgroup analyses were program death-ligand 1 (PD-L1) expression, sarcomatoid features, nephrectomy type, and disease-risk category. Secondary outcomes included grade ≥ 3 adverse events (AEs), immune-related AEs, and treatment discontinuation due to AEs. All outcomes were analyzed using random-effects models owing to inter-study heterogeneity.
Among the four included studies, one demonstrated a significant DFS benefit. There was considerable clinical and statistical heterogeneity (I =64%) due to differences in inclusion criteria and interventions. While pooled results across the four studies did not demonstrate a significant benefit in DFS overall (HR 0.85, 95% CI 0.69-1.04), there was significant benefit among patients with positive PD-L1 expression (HR 0.72, 95% CI 0.55-0.94) and sarcomatoid features (HR 0.59, 95% CI 0.38-0.91).
The evidence base to date regarding ICI as adjuvant therapy in RCC is mixed – conclusions are limited by considerable heterogeneity between studies. However, pooled analyses suggest that patients with positive PD-L1 expression or sarcomatoid features are most likely to benefit from adjuvant immunotherapy.

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