Incidental Findings on Low-Dose CT for Lung Cancer Screening

Low-dose computed tomography (CT) screening lowers lung cancer mortality (NEJM JW Gen Med Feb 15 2021 and N Engl J Med 2020; 382:503). However, low-dose CT also detects potentially clinically significant non–lung cancer incidental findings. In this retrospective study, researchers determined the prevalence and characteristics of clinically significant incidental findings among 26,000 participants (age range, 55–74) in the U.S. National Lung Screening Trial during 2002 to 2009. Eligible participants had ≥30 pack-year smoking history, were current smokers or had quit within the past 15 years, and had undergone at least one of three scheduled low-dose CT screenings.

Clinically significant incidental findings were detected in 34% of participants. A larger percentage of participants with positive lung cancer screens had such findings than did those with negative lung cancer screens (45% and 10%, respectively). The most common clinically significant incidental findings were emphysema (43%), coronary artery calcium (12%), and masses (i.e., kidney, liver, adrenal, and breast; 7%).