Programmed Death Ligand-1 Expression and Its Determinants in Patients with Lung Cancer: A Tertiary Care Center Experience in India

Background: Targeted therapy and immunotherapy have improved survival and quality of life in advanced lung cancer. In this study, we evaluated the frequency of programmed death ligand-1 (PDL-1) expression in lung cancer and its association with different clinical and histological subtypes. Materials and Methods: It is a descriptive observational study, in which patients diagnosed with lung cancer were included. PDL-1 testing was done using the monoclonal antibody PDL-1 SP263 primary antibody. The association between the PLD-1 expression with the clinical parameters and histological grading of the disease was analyzed using the Chi-square test. Results: One hundred and fifty patients were included in our study. The majority of the patients had nonsmall cell lung cancer (90.7%). Among these, 78.7% had adenocarcinoma, 19.1% had squamous cell cancer, and only 2.2% had adeno-squamous cancer. Thirty percent were PDL-1 positive. In patients who were PDL-1 positive, high PDL-1 expression (tumor proportion score ≥50%) was seen in 40%. There was no significant difference seen in PDL-1 expression among different histological subtypes. A significant association of PDL-1 expression was seen with the young age group (34.8% below 60 years vs. 22% above 60 years), and history of tobacco chewing (42% vs. 27%). It was also seen more in men, nonsmokers, in those without history of biomass fuel exposure, less advanced stage, and with no history of pleural invasion. In patients with adenocarcinoma, significantly high PDL-1 expression was seen in those who were negative for EGFR mutation. Conclusion: Our study has found new and different associations between PDL-1 expression and patient outcomes.