THE PROGNOSTIC ROLE OF PRE-TREATMENT PLATELET-TO-LYMPHOCYTE RATIO IN HEAD AND NECK SQUAMOUS CELL CARCINOMA: META-ANALYSIS AND TRIAL SEQUENTIAL ANALYSIS.

Background: Evidence suggests that inflammation contributes to tumor development, from onset to progression and metastasis. Platelet-to-lymphocyte ratio (PLR) is a composite parameter that provides information from two distinct cellular elements, platelets, and lymphocytes. The purpose of this systematic review and meta-analysis is to evaluate the prognostic role of the PLR, in terms of overall survival (OS), disease-free survival (DFS), cancer-specific survival (CSS) and progression-free survival (PFS), in patients with primary head and neck squamous cell carcinoma treated with surgery followed or not by adjuvant therapies.

Materials And Methods: This systematic review was performed according to the guidelines reported in the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Meta-analysis of OS and DFS was performed using the inverse of variance test. Random-effect models were used on the basis of high heterogeneity. Risk of bias assessment, quality of evidence within studies (GRADE) and trial sequential analysis (TSA) were also performed.

Results: The analysis revealed that a higher value of pretreatment PLR correlates with a statistically significant decrease of OS (HR, 1.85; 95% CI: [1.23, 2.80]; P < .00001), confirmed by TSA. The meta-analysis reports an association between high PLR and DFS (HR,1.46; 95% CI: [1.03, 2.06]; P = .003); but TSA suggests that it his should be considered as a false positive. Further studies are needed to validate the efficacy of PLR in predicting CSS and PFS outcomes.

Conclusion: Pretreatment PLR is an independent prognostic factor for OS in HNSCC.