Lung Cancer Screening in a Rural Academic Health System Reveals Low False-Positive Rates

Uptake of lung cancer screening (LCS) suffers from the misconception that LCS produces high false-positive findings. The purpose of this study was to assess LCS results to better quantify these rates.

Retrospective review of patients who underwent LCS at a single, LCS-accredited rural health system from January 2017 to March 2022 was performed. Patient demographics, Lung Reporting and Data Systems (Lung-RADS) score, and follow-up data were reviewed. Using the patient's first LCS scan, the false-positive rate was calculated using Lung-RADS 3 or higher as an indication of a "positive" finding and then calculated using Lung-RADS 4B and 4X alone.

Analyses included 1708 patients, and 89.9% (1536/1708) of these scans were Lung-RADS 1 or 2. Among 80 patients whose first scan resulted in Lung-RADS 3, and 54 patients with Lung-RADS 4a, 61.3% (49/80) and 48.1% (26/54), respectively, received a lower Lung-RADS score on a follow-up scan, allowing them to return to annual screening. Twenty-nine percent (11/38) of those with Lung-RADS 4B or 4X on their first scan were diagnosed with lung cancer. Among the 1708 patients, the false-positive rate on their first scan (Lung-RADS 3 or higher) was 9.4% (159/1695). The rate dropped to 1.6% (27/1695) when only Lung-RADS 4B and 4X was considered a "positive" finding.

Distribution of Lung-RADS scores were in line with national statistics. Results add to mounting evidence that LCS risk of false positives is comparable to mammography, which should encourage clinicians and patients to utilize this life saving screening modality.