Experts' Recommendation for Older, Heavy Smokers
Yearly testing will prevent some lung cancer deaths, experts conclude
Weighing heavily in the task force's latest decision were the results from the U.S. National Cancer Institute's 2011 National Lung Screening Trial. That study, which involved more than 53,000 smokers across the United States, found that annual low-dose CT screenings could prevent one of five lung cancer deaths.
The guidelines revolve around who is at highest risk for lung cancer and who would be able to benefit most from early detection.
Smoking is the biggest risk factor for lung cancer, and causes about 85 percent of lung cancers in the United States. The risk for developing lung cancer increases with age, with most lung cancers occurring in people aged 55 and older.
However, the task force decided to limit CT screenings just to people who either still smoke or quit smoking within the past 15 years. "If you quit more than 15 years ago, because the risk of lung cancer goes down every year from the time you quit smoking, we would take you out of that high-risk category," LeFevre said.
The task force also had to weigh the benefits of early cancer detection against the potential harm caused by regular exposure to radiation from the CT scans, said recommendation co-author Dr. Linda Humphrey, a professor of medicine and clinical epidemiology at Oregon Health & Science University and associate chief of medicine at the Portland VA Medical Center.
"The radiation associated with low-dose CT is on the order of the radiation associated with mammography," Humphrey said earlier this year. "It's not a short-term risk, it's a long-term risk."
She added that there are a fair number of false positives involved in CT scans for lung cancer. These can be resolved through screening, but that adds to the number of radiation exposures a patient will receive.
The panel also had to weigh whether their recommendation would send the message to smokers that they now don't have to quit because screening measures will prevent their death from lung cancer.
"The main message of all this should be that you should stop smoking," said former lung association board chair Rizzo, who is section chief of pulmonary/critical care medicine at Christiana Care Health System in Newark, Del.
"If you have started and you can't quit, there is an ability to screen for that early lung cancer, but the screening does not mean we're going to catch the cancer before it does you harm," Rizzo said. "This is not an excuse for people to keep smoking, simply because they think they can get screened adequately."