Low-Dose CT Screening for Lung Cancer Carries Notable Overdiagnosis Risk

By Amy Orciari Herman

Nearly 20% of lung cancers detected by low-dose computed tomography screening might be indolent, according to a JAMA Internal Medicine study. The researchers say such overdiagnoses should be noted when discussing the potential harms of CT screening.

Using data from the National Lung Screening Trial, the researchers examined lung cancer diagnoses among 50,000 high-risk adults who were randomized to three annual screenings with either low-dose CT or chest radiography. During some 6 years' follow-up, 1089 lung cancers were reported in the CT group and 969 in the radiography group.

Although low-dose CT reduced lung cancer mortality by 20% compared with radiography, there was an 18.5% chance that any lung cancer detected by CT was an overdiagnosis, the researchers estimate.