RT Journal Article SR Electronic T1 Systematic evaluation of the efficacy–effectiveness gap of systemic treatments in metastatic nonsmall cell lung cancer JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1801100 DO 10.1183/13993003.01100-2018 VO 52 IS 6 A1 Christine M. Cramer-van der Welle A1 Bas J.M. Peters A1 Franz M.N.H. Schramel A1 Olaf H. Klungel A1 Harry J.M. Groen A1 Ewoudt M.W. van de Garde A1 , YR 2018 UL http://erj.ersjournals.com/content/52/6/1801100.abstract AB The divergence between clinical trial results and real-world outcomes is largely unknown for many cancer types. The present study aims overall to assess the efficacy–effectiveness gap (difference between outcomes in clinical trials and the real world) in systemic treatment for metastatic nonsmall cell lung cancer (NSCLC).All patients diagnosed with stage IV NSCLC between 2008 and 2014 within a network of seven Dutch large teaching hospitals (Santeon) were studied. For every patient, an efficacy–effectiveness (EE) factor was calculated by dividing individual patients' overall survival (OS) by the pooled median OS assessed from clinical trials with the respective treatment.From 2989 diagnosed patients, 1214 (41%) started with first-line treatment. For all studied regimens, real-world OS was shorter than OS reported in clinical trials. Overall, the EE factor was 0.77 (95% CI 0.70–0.85; p<0.001). Real-world patients completed their treatment plan less often and proceeded less frequently to further lines of treatment. These parameters together with Eastern Cooperative Oncology Group performance status explained 35% of the variation in EE factor.Survival of patients with metastatic NSCLC treated with chemotherapy or targeted therapy in real-world practice is nearly one-quarter shorter than for patients included in trials. Patients' performance status, earlier discontinuation and fewer subsequent lines of treatment partly explained this difference.Survival of patients with metastatic NSCLC treated with chemotherapy or targeted therapy in real-world practice is nearly one quarter shorter than for patients included in clinical trials. These real-world data provide useful information for clinicians. http://ow.ly/Khd230minFF