Improved False-Positive Rates and the Overestimation of Unintended Harm from Lung Cancer Screening

Background: Concern over high false-positive rates and the potential for unintended harm to patients is a critical component of the lack of widespread adoption of lung cancer screening.

Methods: An institutional database was used to identify patients who underwent lung cancer screening between 2/2015 and 2/2018 at Rush University Medical Center and Rush Oak Park Hospital. Reads were executed by dedicated thoracic radiologists and communicated using the Lung Imaging Reporting and Data System (Lung-RADS V.1).

Results: Six hundred and four patients were screened over the study period. We identified 21 primary lung cancers and 8 incidental cancers. We identified a false-positive rate of 17.5%. Only 9 patients underwent further investigative workup for benign disease (5.3%); however, only 4 (2.9%) of those patients were found to have inflammatory or infectious lesions, which are common mimickers of lung cancer. Excluding Lung-RADS category 3 for the purpose of quantifying risk of unintended harm from unnecessary procedures, we found a 6.9% false-positive rate, while diagnosing 25% of all Lung-RADS category 4 patients with primary lung cancer.

Conclusion: False-positive rates in lung cancer screening programs continue to decline with improved radiologic expertise. Additionally, false-positive reporting overestimates the risk of unintended harm from further investigative procedures as only a percentage of positive findings are generally considered for tissue diagnosis (i.e., Lung-RADS category 4).