• Department of Epidemiology, Brown University School of Public Health, Providence, RI; Center for Population Health and Clinical Epidemiology, Brown University, Providence, RI; Melissa_Clark@brown.edu.
• Center for Statistical Sciences, Brown University School of Public Health, Providence, RI;
• Department of Psychiatry, Harvard Medical School, Boston, MA; Cancer Center and Mongan Institute for Health Policy, Massachusetts General Hospital, Boston, MA;
• Schroeder Institute for Tobacco Research and Policy Studies, American Legacy Foundation, Washington, DC; Department of Oncology, Georgetown University Medical Center/Cancer Control Program, Lombardi Comprehensive Cancer Center, Washington, DC;
• Schroeder Institute for Tobacco Research and Policy Studies, American Legacy Foundation, Washington, DC; Department of Oncology, Georgetown University Medical Center/Cancer Control Program, Lombardi Comprehensive Cancer Center, Washington, DC; Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
• Department of Epidemiology, Brown University School of Public Health, Providence, RI; Center for Statistical Sciences, Brown University School of Public Health, Providence, RI;

INTRODUCTION: Lung screening is an opportunity for smoking cessation and relapse prevention, but smoking behaviors may differ across screening results. Changes in smoking were evaluated among 18 840 current and former smokers aged 55-74 scheduled to receive three annual lung screenings.

METHODS: Participants were randomized to low-dose computed tomography or single-view chest radiography in the American College of Radiology/National Lung Screening Trial. Outcome measures included point and sustained (6-month) abstinence and motivation to quit among smokers; and relapse among smokers who quit during follow-up, recent quitters (quit < 6 months), and long-term former smokers (quit ≥ 6 months).

RESULTS: During five years of follow-up, annual point prevalence quit rates ranged from 11.6%-13.4%; 48% of current smokers reported a quit attempt and 7% of long-term former smokers relapsed. Any false positive screening result was associated with subsequent increased point (multivariable hazard ratio HR = 1.23, 95% CI = 1.13, 1.35) and sustained (HR = 1.28, 95% CI = 1.15, 1.43) abstinence among smokers. Recent quitters with ≥1 false positive screen were less likely to relapse (HR = 0.72, 95% CI = 0.54, 0.96). Screening result was not associated with relapse among long-term former smokers or among baseline smokers who quit during follow-up.

CONCLUSIONS: A false positive screen was associated with increased smoking cessation and less relapse among recent quitters. Consistently negative screens were not associated with greater relapse among long-term former smokers. Given the Affordable Care Act requires most health plans to cover smoking cessation and lung screening, the impact and cost-effectiveness of lung screening could be further enhanced with the addition of smoking cessation interventions.