• Tobacco Research and Treatment Center, Massachusetts General Hospital, Boston2Mongan Institute for Health Policy, Massachusetts General Hospital, Boston.
• Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island4Department of Epidemiology, Brown University School of Public Health, Providence, Rhode Island.
• National Center for PTSD, Veterans Affairs Boston Healthcare System, Boston, Massachusetts.
• Massachusetts General Hospital Cancer Center, Boston.
• Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island.
• Tobacco Research and Treatment Center, Massachusetts General Hospital, Boston7Division of General Internal Medicine, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston.

IMPORTANCE: The National Lung Screening Trial (NLST) found a reduction in lung cancer mortality among participants screened with low-dose computed tomography vs chest radiography. In February 2015, Medicare announced its decision to cover annual lung screening for patients with a significant smoking history. These guidelines promote smoking cessation treatment as an adjunct to screening, but the frequency and effectiveness of clinician-delivered smoking cessation interventions delivered after lung screening are unknown.

OBJECTIVE: To determine the association between the reported clinician-delivered 5As (ask, advise, assess, assist [talk about quitting or recommend stop-smoking medications or recommend counseling], and arrange follow-up) after lung screening and smoking behavior changes.

DESIGN, SETTING, AND PARTICIPANTS: A matched case-control study (cases were quitters and controls were continued smokers) of 3336 NLST participants who were smokers at enrollment examined participants' rates and patterns of 5A delivery after a lung screen and reported smoking cessation behaviors.

MAIN OUTCOMES AND MEASURES: Prevalence of the clinician-delivered 5As and associated smoking cessation after lung screening.

RESULTS: Delivery of the 5As 1 year after screening were as follows: ask, 77.2%; advise, 75.6%; assess, 63.4%; assist, 56.4%; and arrange follow-up, 10.4%. Receipt of ask, advise, and assess was not significantly associated with quitting in multivariate models that adjusted for sociodemographic characteristics, medical history, screening results, nicotine dependence, and motivation to quit. Assist was associated with a 40% increase in the odds of quitting (odds ratio, 1.40; 95% CI, 1.21-1.63), and arrange was associated with a 46% increase in the odds of quitting (odds ratio, 1.46; 95% CI, 1.19-1.79).

CONCLUSIONS AND RELEVANCE: Assist and arrange follow-up delivered by primary care providers to smokers who were participating in the NLST were associated with increased quitting; less intensive interventions (ask, advise, and assess) were not. However, rates of assist and arrange follow-up were relatively low. Our findings confirm the need for and benefit of clinicians taking more active intervention steps in helping patients who undergo screening to quit smoking.