Results of a new study published in the Annals of Internal Medicine [Ann Intern Med 152:505-512, 2010] indicate that the risk for false-positive results of CT lung cancer screening tests is substantial. Led by Jennifer M. Croswell, MD, researchers from NCI sought to quantify the cumulative risk in a 1- or 2-year lung cancer screening exam, based on at least one false-positive finding. In addition to determining the rates of false-positive findings, the investigators identified rates of unnecessary diagnostic procedures that are potentially brought on by these false-positive findings. The randomized controlled trial of low-dose CT vs chest radiography (ClinicalTrials.gov registration number: NCT00006382) found that the risks of false-positive results of lung cancer screening tests are substantial after only two annual examinations, particularly for low-dose CT. The authors recommended further study of resulting economic, psychosocial, and physical burdens of these methods.