Background: Squamous cell carcinoma accounts for > 90% of Head and neck cancers and has a poor 5-year survival rate of only 50%. Immunosuppressive agents like PD-L1 inhibitors have been found to improve survival in many tumour types, including advanced/recurrent head and neck squamous cell carcinoma (HNSCC). The PD-L1 expression in this tumour can also predict clinical outcome. However, this fact still remains to be proven.
Aim: The aim was to study the expression of PD-L1 in HNSCC, correlate with clinicopathological parameters and outcome.
Material and method: This prospective study was conducted between March 2021 to June 2023 in department of Pathology of a tertiary care centre located in northern India. A total of 65 histologically confirmed cases of HNSCC were included. Expression of PD-L1 was determined by immunohistochemistry. The combined positive (CPS) and tumour proportion (TP) scores were calculated. The results were correlated with clinicopathological parameters and outcome using appropriate statistical tools.
Results: Considering CPS, 42 (64.6%) cases showed expression of PD-L1. A high score of ≥ 20% was seen in 10 cases (15.4%). PD-L1 expression did not correlate with any of the clinical parameters including age, gender, addiction, site, TNM stage and HPV status. Conventional HNSCC had significantly higher expression of PD-L1. The cases with positive PD-L1 expression had a higher mean survival and a lower mortality, but the difference was not statistically significant.
Conclusion: PD-L1 expression is more likely to be seen in conventional HNSCC histomorphology. PD-L1 expression is a predictor of better prognosis in HNSCC.
Keywords: B7H1; CD274; Combined positive score; Human Papilloma Virus; Immune check point inhibitors; Tumor proportion score.
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