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David S. Ettinger, MD, FACP, FCCP


Impact of Low-Dose CT Screening on Lung Cancer Incidence and Stage Migration

By: Julia Fiederlein
Posted: Friday, October 21, 2022

Although the NLST and NELSON trials have demonstrated favorable shifts in cancer stage and improvements in lung cancer–specific mortality with annual low-dose CT screening, information regarding its effectiveness in clinical practice is limited. In the Journal of Thoracic Oncology, Anil Vachani, MD, MS, of the University of Pennsylvania, Philadelphia, and colleagues examined this issue in a population-based multicenter cohort. 

“Implementation of lung cancer screening at four diverse health-care systems has resulted in a favorable shift to a higher incidence of stage I cancer, with an associated decline in stage IV disease,” Dr. Vachani stated in an International Association for the Study of Lung Cancer (IASLC) press release. “Overall lung cancer incidence did not increase, suggesting a limited impact of overdiagnosis.”

The investigators focused on 3,678 patients who were diagnosed with primary in situ or invasive lung cancer between January 2014 and September 2019 at one of four U.S. health-care systems. Of this study population, 11% were diagnosed after the initiation of lung cancer screening. As the screening volume increased, the proportion of patients diagnosed after the initiation of screening also rose from 0% in Q1 of 2014 to 20% in Q3 of 2019. Lung cancer screening did not seem to result in a significant change in the overall incidence of lung cancer between 2014 and 2018. Stage-specific incidence rates were found to increase and decrease for stage I and IV disease, respectively.

“As screening implementation progresses, future population-based studies are needed to assess the impact of screening on other effectiveness outcomes, including rates of harms related to screening and the impact on lung cancer mortality,” the investigators concluded.

Disclosure: For full disclosures of the study authors, visit

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