Epidemiology and Survival Outcomes for Patients With NSCLC in Scandinavia in the Pre-Immunotherapy Era: A SCAN-LEAF Retrospective Analysis From the I-O Optimise Initiative

ABSTRACT Introduction SCAN-LEAF, part of the I-O Optimise initiative, is a retrospective, longitudinal study investigating epidemiology, clinical care, and outcomes for patients with NSCLC in Scandinavia. We report overall survival (OS) trends for patients diagnosed with NSCLC in Sweden and Denmark between 2005 and 2015. Methods Swedish and Danish cohorts were established by linking national registries. Data on all adults diagnosed with incident NSCLC from January 1, 2005, to December 31, 2015, were included. For temporal analyses of OS trends, patients were stratified by TNM stage and histology. Results Between 2005 and 2015, 30,067 and 31,939 patients from Sweden and Denmark, respectively, were diagnosed with NSCLC; the most common histology was non-squamous cell carcinoma (NSQ; 56.9% and 53.0%) and 48.4% and 51.6% were diagnosed at stage IV. Over the study period, significant improvements in short-term (1-year) survival were observed for patients with NSQ in both countries, regardless of disease stage at diagnosis; however, improvements in longer-term (5-year) survival were limited to patients with stage I and II disease only. Conversely, among patients with squamous cell (SQ) histology, improvements in short-term survival were only observed for stage I disease in Sweden and stage IIIA disease in Denmark, while significant improvements in longer-term survival were seen only for stage IIIA NSCLC in both countries. Conclusion Despite some survival improvements over 2005–2015, an unmet need remains for patients with advanced NSCLC, particularly those with SQ histology. Future analyses will evaluate the impact of newer treatments on OS in NSCLC.