Volume-based, low-dose computed tomographic (CT) screening at various intervals may reduce the risk of lung cancer mortality in people who were current smokers or had a history of smoking, study results published in the New England Journal of Medicine suggest.1
The report was based on lung cancer incidence, mortality, and performance of screenings performed in the Dutch-Belgian lung cancer screening trial (Nederlands-Leuvens Longkanker Screenings Onderzoek [NELSON]). A large number of men in the primary analysis and a smaller proportion of women in the subgroup analyses who currently smoked or had a history of smoking and were between 50 and 74 years of age were randomly assigned to either CT screening (n=6583) or no CT screening (n=6612).
Screening was performed at baseline, 1 year, 3 years, and 5.5 years after randomization. Diagnoses of lung cancer were obtained from linkages with national registries in the Netherlands and Belgium. When possible, a review committee confirmed cancer-related deaths. All participants underwent a minimum follow-up period of 10 years.
Overall, approximately 2.1% of CT scans were positive, which led to a total of 203 screening-detected lung cancers. The 10-year follow-up incidence of lung cancer was 5.58 cases per 1000 person-years and 4.91 cases per 1000 person-years in screening and control groups, respectively (rate ratio, 1.14; 95% CI, 0.97-1.33). In addition, the lung cancer mortality was 2.50 deaths per 1000 person-years in the screening group vs 3.30 deaths per 1000 person-years in the control group.
In the comparison between the screening group and the control group, the cumulative rate ratio for death from lung cancer at 10-year follow-up was 0.76 (95%, 0.61-0.94; P =.01). The investigators reported that similar rate ratios were observed at 8, 9, and 11 years. According to data from the small subset of women, the rate ratio for lung cancer deaths at 10 years was 0.67 (95% CI, 0.38-1.14). Rate ratios at 7, 8, and 9 years were 0.46 (95% CI, 0.21-0.96), 0.41 (95% CI, 0.19-0.84), and 0.52 (95% CI, 0.28-0.94), respectively.
Among men, the excess incidence overdiagnosis rate of lung cancer was 19.7% (bootstrapped 95% CI, -5.2 to 41.6) for screening-detected cases at 10 years. When the researchers extended follow-up to 11 years, however, the overdiagnosis rate decreased to 8.9% (bootstrapped 95% CI, -18.2 to 32.4).
According to an accompanying editorial by Stephen W. Duffy, MSc, and John K. Field, PhD, findings from the NELSON trial establish the benefit of using periodic low-dose CT screening for reducing mortality associated with lung cancer.2 “The task for evaluation is now to estimate the cost-effectiveness of this screening,” they wrote.
1. de Koning HJ, van der Aalst CM, de Jong PA, et al. Reduced lung-cancer mortality with volume CT screening in randomized trial. N Engl J Med. 2020;382:503-513.
2. Duffy SW, Field JK. Mortality reduction with low-dose CT screening for lung cancer. N Engl J Med. 2020;382:572-573.