Implementation of lung cancer screening across five diverse health care systems led to higher rates of stage I diagnoses and lower rates of stage IV disease, study results showed.
Overall incidence of lung cancer did not increase during the study period, indicating a limited impact of overdiagnosis, according to the findings published in Journal of Thoracic Oncology.
Methods
Although results of clinical trials have indicated favorable shifts in disease stage and improvements in lung cancer-specific mortality, “the effectiveness of lung cancer screening in clinical practice has not been clearly demonstrated,” Anil Vachani, MD, MS, associate professor of medicine at Hospital of the University of Pennsylvania and Pittsburgh Veterans Administration Medical Center, and colleagues wrote.
The multicenter cohort analysis included 3,678 patients (median age, 69 years [interquartile range, 64-74]; 52% women) diagnosed with a primary lung cancer between Jan. 1, 2014, and Sept. 30, 2019, across five IU.S. health care systems — Henry Ford Health System, Kaiser Permanente Colorado, Kaiser Permanente Hawaii, Marshfield Clinic Health System and University of Pennsylvania Health System.
Primary outcomes included cancer stage distribution and annual age-adjusted lung cancer incidence. Receipt of at least one low-dose CT scan before lung cancer diagnosis served as the primary exposure variable.
Findings
Overall, 11% (n = 404) of all patients were diagnosed with incident lung cancer after the health care systems initiated low-dose CT screening.
Researchers found that as the volume of lung cancer screening increased, the percentage of patients diagnosed with lung cancer after initiation of screening also increased, from none in 2014 to 20% in 2019. However, lung cancer screening did not correlate with a significant change in the overall incidence of lung cancer between 2014 and 2018 (average annual percentage change [AAPC], 0.8; 95% CI, -4.7 to 3.2).
Researchers additionally observed an average 8.4% increase in the annual rate of stage I cancer (AAPC, 8; 95% CI, 0.8-15.7) and a 6.6% decrease in stage IV disease (AAPC, 6; 95% CI, 11.2 to 0.5).
Implications
“This is the first study to determine the impact of lung cancer screening on cancer stage migration using a population-based multicenter cohort,” Vachani and colleagues wrote. “The distribution of [disease] stage was similar to rates observed in prior clinical trials despite limitations, such as lower adherence to annual screening that have been observed outside of trial settings.”
“As screening implementation progresses,” they added, “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.”
In this study of lung cancer screening at 5 sites, in 3678 individuals, physicians detected 8% more stage 1 lung cancer, which is curable with surgery, and 6% less stage 4 (incurable) cancer. Overall, therefore, the program was catching lung cancer earlier in a screening population, offering a greater prospect of cure. If you’ve ever been a smoker, ask your physician or nurse practitioner about a lung cancer screening low dose CT scan of the chest, which we would be happy to provide for you at INITIO.
