Exhibit Hall | Forum 1
Purpose: To evaluate the diagnostic performance of lung cancer screening (LCS) on low dose CT (LDCT).
Methods: We retrospectively enrolled patients who received LCS via LDCT within our healthcare system between 1/1/2015-6/30/20. Our LCS program is a high-volume, ACR-recognized LCS program that houses a structured reporting registry of Lung-RADS scores. Negative LCS results were defined as Lung-RADS scores of 1 or 2, and positive LCS results were defined as Lung-RADS scores of 3, 4A, 4B, or 4X. Using data from the electronic health record, we defined a malignant pulmonary nodule (i.e., lung cancer) as a pathology-proven diagnosis of lung cancer (via tissue obtained from a needle biopsy, bronchoscopy, or surgical biopsy). We determined the rate of screen-detected lung cancers, as well as all lung cancers diagnosed within one year after a LCS exam. The diagnostic performance of LCS was determined based on receiver operating characteristic analysis. Relevant clinical and demographic characteristics were analyzed as potential confounding factors, including age, sex, race/ethnicity, and smoking history. Potential differences in these factors were evaluated between patients with screen-detected lung cancers and those with negative LCS results.
Results: 5,178 LCS exams were performed on 3,326 unique patients. The average age at LCS was 66±6 years, with 51.4% (1709/3,326) being male. The sensitivity, specificity, test accuracy, positive predictive value (PPV), and negative predictive value of LCS were 95.3%, 84.6%, 84.6%, 13.4%, and 99.9%, respectively. Patients who were current smokers had a higher likelihood of screen-detected lung cancer than former smokers (p=0.0003).
Conclusion: LCS has high sensitivity, modest specificity, and relatively low PPV, the latter suggesting a need for improvements in classification of "positive" LCS results. Screen-detected lung cancers were likely in currently smoking patients.
Low-dose CT, Diagnostic Radiology, Lung