PD-L1 EXPRESSION ANALYSIS IN THE SOUTHERN BRAZIL IN THE LAST THREE YEARS

Introduction: Lung cancer is the leading cause of cancer-related death in the U.S. and worldwide, with nonsmall cell lung cancer (NSCLC) accounting for over 80% of those cases. Programmed death-ligand 1 (PD-L1) expression on tumor cells (TCs) by immunohistochemistry is rapidly gaining importance as a diagnostic for the selection or stratification of patients with NSCLC most likely to respond to single-agent checkpoint inhibitors. Besides, PD-L1 predicts which patients are more likely to respond to immunotherapy. Objective: Epidemiological analysis of patients with non-small cell lung cancer in the Southern of Brazil. Methods: Retrospective study with a sample of 889 patients with non-small cell lung cancer who were tested for PD-L1 in the DAKO 22C3 test during July 2017 to May 2019. Results: When 889 patients were analyzed, 56.8% were males and 43.2% were female. When analyzing the histological subtype, 74.6% presented adenocarcinoma, whereas 25.4% were squamous carcinoma. The prevalence of high-expression PD-L1 defined as greater than 50% was less than two-fifths of the patient population, with 25.9%. Lower expression, defined by < 1%, was 40,7%. Conclusions: The PD-L1 still maintains as the only predictive marker widely used for immunotherapy in advanced lung cancer. As of 2019, it is a mandatory test in any histologic subtype, ideally before any treatment is initiated.