Study: Use of Lung-RADS reduces false positives

The use of the Lung Imaging Reporting and Data System (Lung-RADS) criteria in reporting low-dose CT lung cancer screening results can result in lower false positives, according to a study published in the Annals of Internal Medicine.

Lung-RADS is a system produced by the American College of Radiology (ACR) Lung Cancer Screening Committee as a quality assurance tool designed to standardize lung cancer screening CT reporting and management recommendations. The first version of Lung-RADS was released last year.

Lung-RADS classifies findings in four categories—category 1 (negative), category 2 (benign appearance), category 3 (probably benign) or category 4 (suspicious). All category 3 and category 4 findings are considered positive.

In the study Paul F. Pinsky, PhD, and colleagues retrospectively applied Lung-RADS criteria to the findings of the National Lung Cancer Screening Trial, which included 26,455 individuals aged 55 to 74 years old were at risk for lung cancer. These individuals received at least one low-dose CT screen and a total of 48,671 subsequent screens.

The false positive rate for baseline screenings with Lung-RADS was 12.8% compared to 26.8% for the NLST. For the post-baseline screenings the false-positive rate was 5.3% for Lung-RADS versus 21.8% for the NLST. Baseline sensitivity was 84.9% for Lung-RADS compared with 93.5% for the NLST, and sensitivity after baseline was 78.6%  for Lung-RADS versus 93.8% for the NLST.

“Lung-RADS was designed to reduce the percentage of positive lung screenings and thereby fewer false-positives, without missing clinically significant cancers. And in fact our analysis found it did,” said senior study author Ella Kazerooni, MD, director of cardiothoracic radiology at the University of Michigan Health System, and chair of the ACR Committee on Lung Cancer Screening, in a statement. “Fewer positive screenings means less follow-up testing for patients, which should further improve on the cost-effectiveness of lung cancer screening that was already demonstrated with NLST.”

The publication of this study follows the decision last week by the Centers for Medicare and Medicaid Services to cover low-dose CT lung cancer screening for at-risk Medicare patients.

“The high false-positive rate in the NLST is a potential harm,” said Kazerooni. “By implementing Lung-RADS, we may find that screening can be potentially even more effective.”