Use of Diagnostic CT and Patient Retention in a Lung Cancer Screening Program

The aims of this study were to assess the rate of subsequent diagnostic chest CT examinations in a lung cancer screening (LCS) program and examine the effect on retention of patients in the program.

Patients who underwent LCS CT between June 2011 and August 2018 were included. The occurrence of patients' being subsequently imaged with diagnostic CT versus LCS CT and the effect this had on patients' returning for LCS CT (patient retention) were evaluated. Multivariable logistic regression was used to evaluate variables associated with undergoing diagnostic CT and risk factors associated with loss of patient retention.

Of the 5,912 patients who underwent LCS CT, 2,756 underwent subsequent diagnostic or LCS chest CT. Increasing Lung-RADS® score was more likely to lead to subsequent diagnostic chest CT (P < .0001). A total of 1,240 patients underwent at least three chest CT examinations in the time interval. For the 711 patients whose subsequent CT studies were for LCS, 585 (82%) were retained, whereas of the 529 patients who underwent subsequent diagnostic CT, only 208 (39%) were retained (P < .0001). For the 197 subsequent diagnostic CT examinations performed for pulmonary nodule or screening indications, 81 patients (41%) returned for LCS CT, compared with 498 of 612 patients (81%) who underwent subsequent LCS CT (P < .0001). In multivariable analysis, subsequent diagnostic chest CT and increasing Lung-RADS score were associated with loss of retention.

A higher Lung-RADS score is a risk factor for subsequent diagnostic chest CT, and this is an independent risk factor for loss from the LCS program.