A Retrospective Evaluation of PD-L1 Expression and Heterogeneity in Early-Stage Non-Small Cell Lung Cancer (REPLICA).

Background: Immune checkpoint inhibitors have improved survival in patients with non-small cell lung cancer (NSCLC). Whilst PD-L1 expression is a useful predictive biomarker, data on concordance of expression between primary tumor and nodal metastases in the surgical setting are sparse.

Methods: We assessed PD-L1 expression in paired primary tumor and involved lymph node samples from 451 consecutive patients with stage IIB-IIIB NSCLC who underwent curative lung resection and lymphadenectomy at our institution between 2009 and 2018, to assess intertumor heterogeneity.