The positive predictive value and low false-positive rate arising from these results support the use of low-dose CT for lung cancer screening.
—Nanda Horeweg, MD, and colleagues
The Dutch-Belgian Randomized Lung Cancer Screening Trial (Dutch acronym: NELSON study) was designed to investigate whether screening for lung cancer by low-dose multidetector computed tomography (CT) in high-risk subjects would lead to a decrease in 10-year lung cancer mortality of at least 25% compared with a control group without screening. The study was initiated in 2003, and findings from an evaluation of the screening strategy in the first three rounds of the study, as well as risk calculations made for a follow-up period of 5.5 years, were reported by Nanda Horeweg, MD, of the Department of Public Health and Pulmonology at Erasmus Medical Center in Rotterdam, Netherlands, at the recent European Multidisciplinary Conference in Thoracic Oncology.
Low-dose CT scanning has been proposed as one sensitive screening modality in lung cancer. Proponents estimate that it could detect approximately three times as many small lung nodules as chest x-ray. The NELSON screening strategy considers lung nodules with a volume > 500 mm³ or a volume-doubling time < 400 days positive; volumes of 50 to 500 mm³ or volume-doubling times of 400 to 600 days indeterminate; and all other nodules as negative.
Dr. Horeweg reported that one or more positive screening results were seen in 6% of the subjects, and 200 participants were subsequently diagnosed with lung cancer, yielding a positive predictive value of 40.6% for the scans. False-positive results were seen in just 1.2% of all scans. Over the 5.5-year evaluation, the investigators found that the risk of lung cancer detected by screening was influenced by the results of the first scan; the risk was 1.0% after a negative primary scan at baseline, 5.7% after an indeterminate baseline, and rose to 48.3% in participants with a positive baseline scan.
The authors concluded that the positive predictive value and low false-positive rate arising from these results support the use of low-dose CT for lung cancer screening and provide an additional tool for counseling potential candidates for screening. ■
Disclosure: The study authors reported no potential conflicts of interest.
Horeweg N, van der Aalst C, Vliegenhart R, et al: Volumetric computer tomography screening for lung cancer: Three rounds of the NELSON trial. European Multidisciplinary Conference in Thoracic Oncology. Abstract 150. Presented May 10, 2013.