RT Journal Article SR Electronic T1 Do doctors understand the test characteristics of lung cancer screening? – A randomized trial JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA3808 DO 10.1183/13993003.congress-2016.PA3808 VO 48 IS suppl 60 A1 Richard Schmidt A1 Robab Breyer-Kohansal A1 Marie Kathrin Breyer A1 Matthias Urban A1 Georg-Christian Funk YR 2016 UL http://erj.ersjournals.com/content/48/suppl_60/PA3808.abstract AB Background: Lung cancer screening with CT scan is increasingly being offered to individuals at high risk. However, false-positive results and low mortality reduction are relevant disadvantages that should be explained to screening candidates. This study evaluated whether doctors understand the test characteristics of lung cancer screening.Methods: 556 doctors were invited to answer questions regarding lung cancer screening based on online case vignettes. Half of the participants were randomized to the group 'solutions provided' and received the correct solutions in advance. The group 'solutions withheld' had to rely on prior knowledge or estimates.Results: Response rate was 29%. The reduction in the number of deaths due to screening was overestimated six-fold (95%CI: 4 to 8) compared with the actual data. Providing the correct solutions to doctors had no systematic effect on their answers. Compared with actual data from the literature, the prevalence of lung cancer was overestimated three-fold, while the prevalence of suspicious screening results, specificity, positive predictive value, and false-negative rate were underestimated.Conclusion: Doctors poorly understand the test characteristics of lung cancer screening. Offering the correct solutions in advance did not improve the answers. Continuing education regarding screening and the interpretation of test characteristics may be a remedy.