More than 18% of all lung cancers detected by low-dose computed tomography (LDCT) present an over-diagnosis, according to researchers at Duke University Medical Center. The findings were recently published online via JAMA Internal Medicine. Investigators believe this is potentially harmful, because of additional costs of LDCT, along with anxiety and complications associated with unnecessary treatment.

Using data from the National Lung Screening Trial, researchers compared results from LDCT screening to those from chest radiography on patients at high risk for lung cancer.

Among 1,089 lung cancers reported in the LDCT group during follow-up, the authors estimated that 18.5% represented an over-diagnosis. They further estimated that 22.5% of non-small cell lung cancer detected by LDCT represented an over-diagnosis and that 78.9% of bronchioalveolar (air sacs) lung cancers detected by LDCT represented an over-diagnosis.

“In the future, once there are better biomarkers and imaging techniques to predict which individuals with a diagnosis of lung cancer will have more or less aggressive disease, treatment options can be optimized, and a mass screening program can become more valuable,” the authors concluded.