FROM AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE
Smoking abstinence for 7 years results in a 20% reduction in death from lung cancer – a benefit that is comparable to three rounds of annual screening with low-dose helical computed tomography (LDCT) – in asymptomatic individuals with at least a 30–pack-year smoking history, based on a secondary analysis of 50,263 participants in the National Lung Screening Trial (NLST).
Not smoking for 7 years plus screening for lung cancer with LDCT conferred an additional 10% reduction in lung cancer mortality. Similar patterns for smoking cessation benefits were noted for overall mortality, as well.
“This study is the first to quantify the benefit of smoking cessation coupled with lung cancer screening in a cohort that is asymptomatic,” wrote Dr. Nichole T. Tanner of the Medical University of South Carolina, Charleston, and her colleagues (Am J Respir Crit Care. 2016 March 1. doi: 10.1164/rccm.201507-1420OC). “[Its] findings highlight the importance of integrating smoking cessation efforts into lung cancer screening programs.”The NLST subset study included 47,902 participants who self-identified as non-Hispanic white and 2,361 who self-identified as non-Hispanic black; 24,190 were current smokers and 26,073 were former smokers who had quit within the 15 years prior to entering the study. Participants ranged in age from 55 to 74 years at the time of randomization and had a 30–pack-year or more history of cigarette smoking.
All participants were screened for lung cancer with either LDCT or a chest radiograph examination. A 20% reduction in death from lung cancer was seen in those who had abstained from smoking for 7 years and were screened for lung cancer with a chest radiograph and in those who had undergone three rounds of annual screening for lung cancer with LDCT and continued to smoke.
For former smokers screened with LDCT, the risk of dying of lung cancer decreased at a faster rate than it did for those screened with chest radiographs. For each additional year an individual abstained from smoking and had an LDCT screen, the risk of dying of lung cancer decreased by 9%. For those individuals who abstained from smoking and had been screened with a chest x-ray, the risk of dying of lung cancer decreased by 3%.
In contrast, there was a 10% increase in lung cancer mortality for each additional 10 pack-years smoked for those screened with LDCT (HR, 1.10; 95% CI, 1.08-1.13). This “did not vary significantly in the chest radiograph group,” according to the researchers.
In both screening groups, “an additional 6% risk of death from all causes (was seen) for each additional 10 pack-years smoked.”
In addition, black study participants who had quit smoking at trial entry had “a more pronounced benefit” from having done so, compared with the white study participants (HR, 0.53, 95% CI, 0.28-1.0).
The NLST was sponsored by the National Cancer Institute. Dr. Nichole T. Tanner, one of this secondary analysis’s authors reported receiving grants from ACCP OneBreath Foundation for her work on this project and grants from Olympus America, Cook, and the American Cancer Society for other work. Disclosures for all investigators are available at atsjournals.org.
