Using Lung Imaging Reporting and Data System (Lung-RADS) criteria developed by the American College of Radiology (ACR) to interpret low-dose CT (LDCT) lung screening results may reduce false positives compared to the National Lung Screening Trial (NLST), but the trade-off is reduced sensitivity, according to an article published in Annals of Internal Medicine.
Recently, the U.S. Preventive Services Task Force recommended lung cancer screening with LDCT for high-risk populations based primarily on the NLST, which defined a positive screen as a nodule 4-mm or larger. This definition is important because it determines how patients are managed in clinical practice. Since then, discussion has focused on whether increasing the nodule size cutoff could reduce the substantial false positive rate of the NLST, a major harm and cost driver of LDCT lung cancer screening.
The ACR developed Lung-RADS as a way to standardize the reporting of CT lung screens. Under Lung-RADS criteria, the size threshold for a positive baseline screen was raised to 6-mm. The goal was to determine the most effective definition of a positive screen, reduce the false positive rate seen with NLST criteria, and suggest management recommendations based on lung cancer risk. When retrospectively applied to NLST, Lung-RADS substantially reduced the false positive rate, but sensitivity was also lower. The authors suggest more research to determine the clinical impact of utilizing Lung-RADS in clinical practice.