The predictive role of PD-L1 in head and neck cancer: A systematic review and meta-analysis

This systematic review and meta-analysis investigates the predictive and prognostic role of PD-L1 expression in treating head and neck squamous cell carcinoma (HNSCC). Recognizing the importance of PD-L1 in patient response to treatment, the main objective was to assess its impact on overall survival and progression-free survival in HNSCC patients. A thorough search of databases such as PubMed, Scopus, and Web of Science from 2010 to 2022, along with relevant articles and references, yielded 120 studies. Of these, 7 met the criteria focusing on HNSCC patients, PD-L1 expression evaluation, and treatment with PD-1 or PD-L1 inhibitors. Data extraction followed PRISMA guidelines and involved independent review and consensus for discrepancies. The primary outcomes analyzed were overall survival and progression-free survival in relation to PD-L1 expression levels in patients undergoing immunotherapy. The seven randomized controlled trials selected had a total of 4,477 participants. Results showed that patients with positive PD-L1 expression experienced improved overall survival when treated with PD-1 or PD-L1 inhibitors, particularly those with high PD-L1 expression. However, PD-L1 expression did not significantly affect progression-free survival. These findings suggest that PD-L1 expression can be a predictive marker for better overall survival in HNSCC patients treated with immunotherapy. However, its influence on progression-free survival remains unclear, indicating the need for further research.