Hi, everyone. I'm Dr Kenny Lin. I am a family physician at Georgetown University Medical Center, and I blog at Common Sense Family Doctor.
In July, the US Preventive Services Task Force (USPSTF) posted a draft recommendation statement on lung cancer screening, updating its 2013 recommendation to offer annual low-dose CT for current or former smokers from age 55 to 80 years with at least a 30–pack-year smoking history. The updated recommendation expands screening eligibility to younger adults age 50-54 years and lowers the minimum smoking threshold to 20 pack-years. The new screening criteria are based on a decision analysis that found that it would further reduce lung cancer deaths and increase life-years gained compared with the 2013 screening strategy. Also, the recent Dutch-Belgian NELSON trial of lung cancer screening, which enrolled younger and lighter smokers than the US National Lung Screening Trial (NLST), found a lung cancer mortality benefit.
The USPSTF draft statement coincided with an independent meta-analysis of low-dose CT screening published in the Journal of General Internal Medicine. This analysis pooled the results of nine randomized controlled trials (including NELSON and NLST) with nearly 100,000 participants and found that low-dose CT reduced lung cancer mortality by 16%, with a number needed to screen of 265 to prevent one lung cancer death. However, screening did not reduce overall mortality.
For the past several years, I have cautioned family physicians against rushing into screening for lung cancer, pointing to the American Academy of Family Physicians (AAFP) 2013 statement that there was insufficient evidence to recommend low-dose CT screening despite it being endorsed by the USPSTF. The AAFP's concerns at that time could be briefly summarized as: single study, generalizability uncertain, many false positives, overdiagnosis.
Today, multiple studies have confirmed the NLST's findings and the ability of community radiology centers to meet the same technical standards and low adverse event rates as academic institutions. Most recently, an integrated health system in Portland, Oregon, reported on the results of more than 6000 low-dose CT screenings in 3400 patients who underwent 226 invasive interventions, leading to adverse events in 21 patients (pneumothorax being the most common). Two of 85 patients who underwent lung cancer surgery died.
As for false positives and overdiagnosis, the Journal of General Internal Medicine analysis found that 8% of initial low-dose CT findings were false positives and that fewer than 1 in 1000 patients with false-positive results experienced a complication from a diagnostic procedure. Based primarily on the NELSON trial, the researchers reported an overdiagnosis rate of 9% after a decade of follow-up, considerably lower than the NLST estimate of 20%.
The quality and quantity of data supporting lung cancer screening have changed, so I've changed my mind. Family physicians should continue to counsel current smokers to quit, but we can do more to prevent lung cancer morbidity and mortality by offering low-dose CT screening to eligible patients (including those who have quit within the past 15 years) as defined by the USPSTF. Given the nontrivial harms involved, shared decision-making remains important, but public and private payer requirements should be streamlined in order to make delivering this preventive service no more difficult than screening for breast or colorectal cancer.
This has been Dr Kenny Lin for Medscape Family Medicine. Thank you for reading.
Kenny Lin, MD, MPH, teaches family medicine, preventive medicine, and health policy at Georgetown University School of Medicine. He is deputy editor of the journal American Family Physician.
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Cite this: I've Changed My Mind on Lung Cancer Screening - Medscape - Aug 18, 2020.