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

INTRODUCTION: SCAN-LEAF, part of the I-O Optimise initiative, is a retrospective, longitudinal study investigating the 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, a total of 30,067 and 31,939 patients from Sweden and Denmark, respectively, were diagnosed with NSCLC; the most common histological subtype was nonsquamous cell carcinoma (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 survival (1 y) were observed for patients with nonsquamous cell carcinoma in both countries, regardless of disease stage at diagnosis; however, improvements in longer-term survival (5 y) were limited to patients with stage I and II disease only. Conversely, among patients with squamous cell 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. CONCLUSIONS: Despite some survival improvements between 2005 and 2015, an unmet need remains for patients with advanced NSCLC, particularly those with squamous cell histology. Future analyses will evaluate the impact of newer treatments on OS in NSCLC.