Prevalence of PD-L1 Expression in Non-Small Cell Lung Cancer: A Real-World Analysis From Jordan

Lung cancer remains the leading cause of cancer-related mortality worldwide. Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 pathway have significantly improved survival outcomes in non-small cell lung cancer (NSCLC), and treatment selection is influenced by the degree of PD-L1 expression. Although ICI use began in 2017, there is a lack of data on PD-L1 expression in NSCLC among Jordanian patients. This study aimed to estimate the prevalence of PD-L1 expression and its association with demographic, clinical, and molecular characteristics, including EGFR mutation and ALK rearrangements.

This retrospective observational study reviewed electronic medical records for all patients with lung cancer diagnosed at King Hussein Cancer Center from January 1, 2017, to April 1, 2024. Included patients had histologically confirmed NSCLC and were tested for PD-L1 expression. PD-L1 expression was considered positive if the tumor proportion score (TPS) was ≥1%. Descriptive statistics were performed to summarize patient characteristics. Comparisons between TPS 1%-49% and TPS ≥50% groups were performed using chi-square tests.

Of the 1,872 screened patients, 1,508 met the inclusion criteria and were included in the analysis. In this sample, the majority of patients were male (79%), former smokers (70%), presented with advanced disease (stage III/IV, 86%), and had adenocarcinoma histology (71%). Approximately 25% presented with squamous cell carcinoma. The prevalence of PD-L1 positivity was 68% (n = 1,022). Among the PD-L1-positive patients, 59% had TPS 1%-49% and 41% had TPS ≥50%. Among patients tested for EGFR mutation and ALK fusion, alterations were identified in 16.6% and 8.4% of tested patients, respectively. In PD-L1-positive tumors, EGFR wild-type status was significantly associated with high PD-L1 expression (TPS ≥50%) compared with EGFR-mutated tumors (56% v 44%, P = .007).

This first comprehensive analysis of PD-L1 prevalence in patients with NSCLC in Jordan demonstrates a relatively high prevalence of both PD-L1 positivity (≥1%) and high expression (≥50%) compared with reported data from other regions. Distinct molecular associations were observed, with higher PD-L1 expression in ALK-rearranged and EGFR wild-type tumors. These findings underscore the need for prospective and multicenter studies to further identify the biologic and clinical implications of PD-L1 expression in Jordanian patients with NSCLC.