Regional variations in molecular testing and treatment of patients with metastatic NSCLC in the Netherlands

BACKGROUND: Molecular testing combined with targeted therapy has led to a rapid improvement of patient outcomes in metastatic non-small cell lung cancer (NSCLC). However, previous reports suggested that the use of these treatment modalities might vary between geographic regions within countries. We aimed to examine variation in diagnostics and treatment of non-squamous metastatic NSCLC. METHODS: We compared five Dutch regions using population-based data from the Netherlands Cancer Registry (2020-2023). Variation in molecular testing and first-line targeted therapy across regions was assessed with the likelihood-ratio test (LRT) of a multivariable logistic regression model. This model included region as a variable, and accounted for patient characteristics such as sex, age, programmed death-ligand 1 (PDL-1) status, year of diagnosis and World Health Organization performance status. Variation in treatment was also assessed with the LRT in patients with actionable genetic aberrations. RESULTS: A total of 16,655 patients (median age 69 [62, 75]; 52% male) were diagnosed with metastatic non-squamous NSCLC. Of these patients, 14,297 (86%) underwent molecular testing, ranging from 82% to 91% between regions (p < 0.001). 1470 patients had an actionable genetic aberration, of which 1252 (85%) received targeted therapy, ranging from 82% to 89% (p = 0.17). CONCLUSION: The application of molecular testing in metastatic non-squamous NSCLC varies across regions in the Netherlands, while minimal variation was observed in the application of targeted therapy. These findings highlight the need for better collaboration between regions to optimize guidelines and ensure uniform care.