Computed Tomography Screening for Lung Cancer: What Is a Positive Screen?

The NLST (National Lung Screening Trial) showed thatscreening with low-dose thoracic computed tomogra-phy (CT) reduces lung cancer mortality by 20 % (1). Sev-eral organizations recommend (2) or suggest (3) that clinicians offer screening to persons who meet either the NLST criteria for lung cancer risk or modified versions of these criteria if comprehensive multidisciplinary coordi-nated care and follow-up similar to those provided to NLST participants are available. A major issue for practical and cost-effective implementation of low-dose CT screen-ing for lung cancer is the definition of a positive scan. A positive low-dose CT scan, by definition, triggers diagnostic work-up. Most recommended paths for such work-up entail repeating CT before the next annual CT but may include biopsy or even surgical resection, which can cause the patient unnecessary harm if the result wa