PDL-1 TESTING AND IMMUNOTHERAPY SELECTION—EARLY LABORATORY EXPERIENCE AND ITS POTENTIAL ROLE IN HEAD & NECK CANCER MANAGEMENT

Background and Objective Anti-programmed cell death protein 1 (PDL-1) therapy has been relatively recently approved in a defined context by NICE in adults for the management of recurrent and metastatic head and neck squamous cell carcinomas (HNSCCs). In this context, companion diagnostic PDL-1 testing, previously established at our center for lung and bladder tumors, was undertaken as per NICE recommendations and clinical requests in a few head and neck cases. Methods Histopathology reports incorporating PDL-1 test results were identified (5-year period January 2014 to January 2020; including HNSCCs)) and analyzed for tumor type, clone, and test result. Results PDL-1 testing was undertaken in 199 cases, including 3 with HNSCC, with low focal positive staining in all 3 cases (1%, 1%, and 15%). Conclusions Immunotherapy treatment in HNSCC has demonstrated a small but statistically significant improved overall survival in some studies. The strength of correlation between PDL1 expression and response to immune-oncology agents in HNSCC has, however, been established to a lesser degree in recent studies as opposed to some other tumor types, such as in lung carcinoma. This study aims to record data as per NICE recommendations and share them with a view to highlighting the case for improved routine laboratory biomarkers in HNSCC.