The U.S. Preventive Services Task Force has released draft recommendations calling for annual low-dose computed tomography scans to screen for lung cancer in high-risk populations.

Draft recommendations recently released by the U.S. Preventive Services Task Force (USPSTF) that call for annual low-dose computed tomography (LDCT) scans to screen for lung cancer in high-risk populations could lead to a major shift in the way lung cancer is detected.

Lung cancer kills approximately 160,000 Americans each year, and the Centers for Disease Control and Prevention attributes nearly 130,000 of those deaths to smoking. The USPSTF recommendations are aimed at the estimated 8 to 10 million current and former smokers ages 55 to 79 who have smoked a pack a day or more for 30 years, or heavy smokers who have quit within the past 15 years.

“Nearly 90% of people who have lung cancer die from it, at least in part because the cancer is advanced at the time of diagnosis,” says Virginia Moyer, MD, MPH, chair of the USPSTF. “If caught early, the lung cancer that occurs in smokers may be curable.”

The draft recommendations, updated from 2004 guidelines, are based primarily on evidence from the National Lung Screening Trial (NLST). The study, published in 2011 in the New England Journal of Medicine, followed 53,000 long-term heavy smokers and former smokers for a mean of 6.5 years and compared LDCT screening to screening with chest X-rays. “Chest X-rays are simply not sensitive enough to find a lung cancer at an early stage, so the study was similar to comparing CT scans with no screening, which is currently the standard,” says Moyer.

The study, which involved scanning participants three times at 1-year intervals, showed a 20% reduction in lung cancer deaths in the group receiving LDCT scans, and that approximately 320 people would need to be scanned to diagnose one case of lung cancer. The USPSTF cites false positives, false negatives, incidental findings, overdiagnosis, and radiation exposure as harms associated with LDCT.

Based on data from the NLST and results from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (published in the Journal of the National Cancer Institute in 2010), the Cancer Intervention and Surveillance Modeling Network identified the age ranges, smoking exposures, and scan intervals that would provide the best balance between harm and benefit. “The parameters we ultimately used in our recommendations show a roughly 14% to 16% reduction in lung cancer deaths with annual LDCT screenings,” says Moyer.

“The recommendations are very much in line with what many other organizations are calling for,” notes Peter Bach, MD, a pulmonary specialist and director of the Memorial Sloan-Kettering Cancer Center's Center for Health Policy and Outcomes in New York, NY. “The science is solid.”

Still, “the idea that screening will save 20,000 lives annually is wildly optimistic,” Bach cautions. “The populations of patients we're looking at will be difficult to enroll and follow, and the quality of care and follow-up varies by institution.”

Additionally, “I hope the final recommendations will encourage primary care physicians to have a conversation with each patient,” he says. “An older, heavy smoker may have a 1 in 80 chance of benefiting, while a younger, lighter smoker, who still falls within screening parameters, may have only a 1 in 1000 chance of benefiting. There are a variety of screening decision tools to assess individual risk.”

“It's important to note that screening is likely to prevent only a modest proportion of the deaths,” adds Moyer. “Screening is not a substitute for quitting or never starting to smoke.”

The USPSTF is accepting public comments on the draft recommendations until August 26. Final recommendations are expected within 3 to 6 months of that date.