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In June 2011, the New England Journal of Medicine published results from the landmark National Lung Screening Trial (NLST) that showed a 20% mortality reduction in a high-risk population who had undergone low-dose CT. In 2020, a second high quality trial (NELSON) performed in Europe confirmed the benefit of low dose screening CT with a mortality reduction of 26% in high-risk men and a potentially even greater benefit in screened women. Learn more about lung cancer.
Following the 2011 NLST, the National Comprehensive Cancer Network (NCCN) issued guidelines recommending low-dose CT screening for lung cancer, and the United States Preventive Services Task Force (USPSTF) issued their recommendation for annual low-dose CT screening in high-risk individuals at the end of 2013. In March 2021, the USPSTF broadened the screening eligibility criteria.
Eligible patients must be referred by a physician and active smokers undergoing screening CT should enter a smoking cessation program. We re-iterate that screening is not an alternative to smoking cessation which is the most important action that can be taken by current smokers to minimize their likelihood of developing cancer. Visit our Smoking Cessation Program to join or learn more.
Left: 65 year-old woman
Right: Eight months later
Over the period that NLST participants were screened, approximately 40% of individuals had a positive CT result, usually consisting of small indeterminate pulmonary nodules considered suspicious for lung cancer, on at least one of the three annual tests. Of these initial findings, 96% were false positives, but required diagnostic follow-up, mostly with further imaging, and in some cases involving invasive procedures such as bronchoscopy, biopsy or surgery. The death rate from any cause in the CT screening group was reduced by 6.7%, compared to the radiography group. One death from lung cancer was prevented per 320 participants in screening.
Radiation dose reduction and optimization
At Stanford Health Care, we understand that radiation exposure is a concern to referring physicians and patients. We are committed to reducing radiation exposure and following radiation safety principles. CT lung cancer screening will be a low-dose CT exam, with a radiation dose equivalent to approximately half of the naturally occurring background radiation that a person receives for one year at sea level. This exam does not require intravenous contrast.
The Centers for Medicare & Medicaid Services (CMS) proposes that the evidence is sufficient to add a lung cancer screening counseling and shared decision making visit, and for appropriate beneficiaries, screening for lung cancer with low dose computed tomography (LDCT), once per year, as an additional preventive service benefit under the Medicare program only if all of the following criteria are met: