PD-L1 Expression in Head and Neck Squamous Cell Carcinoma and Its Clinical Significance: A Prospective Observational Study from a Tertiary Care Centre

Background: Programmed Death Ligand 1 (PD-L1) expression in tumor cells contribute to tumor immunity and therapies directed against it, have shown encouraging results in recent years. As there is limited data on the significance of PD-L1 expression in Head and Neck Squamous Cell Carcinoma (HNSCC) from India, we aimed to study the PD-L1 expression and its relation with different clinic-pathological parameters in patients of HNSCC from a tertiary care center in Eastern India. Methods: A prospective evaluation of HNSCC patients diagnosed and managed at our center over a period of two and half years, was performed. PD-L1 expression in formalin fixed-paraffin embedded tumor tissue specimens was measured using SP-263 (Ventana) and 22C3 (Dako). A PD-L1 expression of <1%, 1–19%, ≥20% were considered negative, low, and high expression, respectively, and was correlated with various parameters. Results: A total of 71 patients (mean age 50.8 ± 13.3 years, 86% males) were diagnosed with HNSCC (buccal mucosa-28, tongue-22, rest of oral cavity-8, larynx-7, nasopharynx-6). The tumor was poorly differentiated in 12 (17%). PD-L1 positivity was seen in a total of 51 (71.8%) patients (1–19%:18, ≥20%:33). Thirty (85.7%) patients among those aged <50 years and 58.3% of those aged ≥50 years showed PD-L1 positivity which was significant (P = 0.01). There were no statistically significant differences in PD-L1 positivity with respect to gender, tobacco use, tumor grade as well as tumor and nodal stage. Median follow up duration was 18 months (range 3–31 months) and there was significant difference in overall survival among PD-L1 positive and negative groups (31 vs 24 months; log rank P = 0.03). Conclusions: 72% of HNSCC patients in our cohort showed PD-L1 positivity and it was not associated with any patient demographic characteristics or aggressive pathological features. Positive PD-L1 expression may have a beneficial effect on overall survival in HNSCC.