The following is the summary of “Stage Migration and Lung Cancer Incidence After Initiation of Low-Dose Computed Tomography Screening” published in the December 2022 issue of Thoracic oncology by Vachani, et al.

Clinical trials have shown that lung cancer screening (LCS) reduces cancer-related mortality and reduces cancer’s advanced stage, but its efficacy in actual clinical practice has not been established. Our multicenter cohort study included patients diagnosed with primary lung cancer at one of four U.S. health care systems between January 1, 2014 and September 30, 2019. The age-adjusted rate of new cases of lung cancer each year and the distribution of cancer stages were the primary endpoints. Low-dose computed tomography(CT) for lung cancer screening was the key exposure variable.

There were a total of 3,678 new cases of lung cancer identified over the study period, with 404 of those cases identified after LCS was started (or 11% of the total). The percentage of patients diagnosed with lung cancer following the implementation of LCS grew from 0% in the first quartile of 2014 to 20% in the third quartile of 2019 as screening volumes rose. The incidence of lung cancer did not change noticeably between 2014 and 2018 as a result of LCS (average annual percentage change [AAPC]: 0.8 [95% confidence interval (CI): -4.7 to 3.2]). Incidence rates varied by stage, with a rise seen for stage I cancer (AAPC = 8.0; 95% CI, 0.8-15.7) and a decrease seen for stage IV disease (AAPC = -6.0; 95% CI,- 11.2 to -0.5).

There has been a positive trend toward a higher incidence of stage I cancer and a corresponding drop in stage IV disease since LCS was implemented in 4 different healthcare systems. However, overdiagnosis may not have had much of an effect, given the overall lung cancer incidence rate was not higher.