PD-L1 expression shows subtype-specific prognostic value in skin neoplasms, meta-analysis finds

This systematic review and meta-analysis examined the prognostic significance of PD-L1 expression across various skin neoplasms, synthesizing data from 24 observational studies. The patient population comprised individuals with different skin cancers from the included studies, though specific sample sizes and settings were not reported. The analysis focused on PD-L1 expression as a biomarker, without a direct clinical intervention comparator, assessing outcomes including overall survival (OS), disease-free survival (DFS), and risk of lymph node metastasis in squamous cell carcinoma.

The primary analysis found PD-L1 expression was not significantly associated with OS across all neoplasms (HR = 0.89, 95% CI: 0.70-1.12) or with DFS (random-effects HR = 0.86, 95% CI: 0.54-1.38). However, subgroup analyses revealed subtype-specific associations. In Merkel cell carcinoma, PD-L1 expression was associated with improved OS (HR = 0.39, 95% CI: 0.18-0.83). For DFS, PD-L1 expression predicted better outcomes in melanoma and cutaneous squamous cell carcinoma, but worse DFS in cutaneous angiosarcoma and sebaceous gland carcinoma. Additionally, in squamous cell carcinoma, PD-L1 expression was significantly associated with an increased risk of lymph node metastasis (OR = 5.33, 95% CI: 2.21-12.89).

Safety and tolerability data were not reported in this biomarker analysis. The authors note this evidence represents association, not causation, and stems from a meta-analysis of observational studies where heterogeneity and publication bias were assessed. Key limitations, including potential confounding and variation in PD-L1 assay methods across studies, were not detailed. The practice relevance is restrained; these findings describe prognostic associations in specific contexts but do not establish clinical utility for PD-L1 testing or guide treatment decisions without intervention data.