PD-L1/PD-1 Expression in the Treatment of Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders: An Overview of Reviews

: Objective: In this overview, we present compelling evidence from multiple systematic reviews and meta-analyses (SRMAs) and examine the prognostic role of the PD-L1/PD-1 axis, as well as the potential of personalized treatment strategies targeting this axis, in patients with oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). Methods: Six databases were searched to retrieve systematic review and meta-analysis studies. The population of interest was patients with OSCC and OPMDs in whom the expression of PD-L1 and PD-1 had been investigated. At least one of the following outcomes was reported, along with at least one clinicopathological feature: overall survival, disease-free survival, or disease-specific survival. All studies were assessed for risk of bias using the AMSTAR 2 tool. Results: A total of 195 studies were found through the initial search, and after duplicate removal, 97 studies were screened by title and abstract. Finally, five systematic reviews and meta-analysis studies fit our inclusion criteria and were included in this review. Conclusions: Based on two published systematic reviews, our study revealed a lack of evidence for the prognostic value of PD-L1 in improving overall survival in oral cancer patients. However, it showed a correlation with specific clinicopathological features such as sex, lymph node metastasis, and HPV status.