e18249 Background: The indications and use of immune checkpoint inhibitors (ICIs) in the treatment of advanced and metastatic lung cancer have grown dramatically since the first lung cancer drug approval in 2015. The rapid pace of change can make it difficult for oncologists to stay up to date with how best to integrate these news agents into treatment paradigms. The objective of this study was to assess trends over time in oncologists’ knowledge, competence, and confidence using ICIs in the treatment of lung cancer. Methods: A series of online continuing medical education (CME) activities about the role of ICIs in lung cancer treatment was launched in April 2014; 28 included multiple-choice knowledge/competence questions and a confidence question assessed on a 5-point Likert-type scale before and immediately after the activity. Activities that had at least 30 oncologists participate pre/post are included in this analysis. A pre-/post-assessment study design was used, and educational effect was assessed with Chi-square tests. Analyses were conducted to examine trends in knowledge, competence, and confidence over four years on a quarterly basis. Weighted averages in each of the outcomes were calculated by quarter. Results: A total of 132,370 learners participated from April 2014-March 2018, including 61,761 physicians, of whom 19,439 were oncologists. The average increases pre- to post-test for knowledge- (25 activities), competence- (18 activities), and confidence-based (9 activities) questions were 16%, 12%, and 7%, respectively (P < 0.001 for all comparisons). The absolute increase in knowledge from pre-test in 2014 (41%) to post-test in 2018 (56%) was 14 percentage points; and for competence, 25% (from 28% in 2014 to 52% in 2018). The mean confidence rating pre-test in 2016 was 2.85 versus 3.16 post-test in 2018. Conclusions: Online CME improves oncologists’ knowledge, competence, and confidence using ICIs in the treatment of lung cancer at any given point in time; however, gaps remain, and given the wealth of new data that continue to emerge, on-going education is needed to reinforce and build upon existing knowledge, close persistent gaps, and increase oncologists’ confidence with this new therapeutic class.