CT scans have been proven to help spot lung cancer early and save lives. Now, updated expert recommendations could double the number of Americans who are eligible for the yearly screening.
The recommendations -- from the U.S. Preventive Services Task Force (USPSTF) -- would expand the definition of "high risk" for lung cancer. That's expected to not only increase the number of people eligible for screening, but also to have a particular benefit for women and Black Americans.
Right now, annual screening with a low-dose CT scan is recommended for 55- to 80-year-olds who have smoked at least 30 "pack-years" over a lifetime, and either still smoke or have quit within the past 15 years.
The new recommendations would shift that starting age to 50. And screening would be an option for people who smoked less heavily -- the equivalent of 20 pack-years.
In plain English, that translates to one pack of cigarettes per day for 20 years, or two packs a day for 10 years, for example.
The proposed changes are based on research done since the first USPSTF recommendations came out in 2013, according to task force member Dr. Michael Barry.
He said the latest evidence comes from a clinical trial called NELSON. It followed more than 15,700 people ages 50 to 74 who were randomly assigned to either CT screening or no screening.
Over 10 years, those who underwent screening were 24% less likely to die of lung cancer.
The American Lung Association (ALA) "enthusiastically" welcomed the proposed new recommendations.
Lung cancer remains the top cancer killer in the United States, said ALA President Harold Wimmer. Only around 22% of Americans diagnosed with the disease are still alive five years later.
A major reason, he explained, is that the cancer is typically detected only after it is more advanced.
"Lung cancer is much more curable when diagnosed at an early stage, making screening key to turning the tide against this deadly disease," Wimmer said.
With any screening test, there are potential harms. One is the risk of a false-positive result, where a test incorrectly suggests cancer is present.
A large U.S. trial found that about one-quarter of first-time CT screenings yielded a false-positive. But, Barry said, the chance of that leading to an invasive procedure (like a needle biopsy) was "much smaller."
For every 1,000 people screened in the trial, false-positives led to invasive procedures in 17, the USPSTF says.
The panel also found a very small risk of radiation-induced cancer -- in the range of roughly 0.3 to 0.8 cancers for every 1,000 people screened annually for 10 years.
Of course, recommendations only matter if they are put into effect. And even though lung cancer screening has been recommended for some people since 2013, "uptake has been low," Barry said.
Last year, an ALA report found that in 2018, only 4% of eligible Americans were screened for lung cancer.
It cited several potential reasons -- including the newness of using CT scans for that purpose, and a lack of awareness not only among patients, but among doctors, too.
Expanding awareness is critical, Barry said. The new recommendations are expected to have a particular effect on the number of women and Black Americans who are newly eligible for screening. Compared with white men, they tend to smoke fewer cigarettes.
Then there is the cost. The USPSTF is a government-funded panel of volunteer medical experts, tasked with reviewing evidence and making recommendations on preventive health care, such as cancer screenings.
Medicare and most private health plans are required to cover USPSTF-recommended screenings. But Medicaid -- the government insurance program for low-income Americans -- does not necessarily cover it. Each state has different policies, according to the ALA.
Ultimately, Barry said, the best way to lower the risk of dying from lung cancer is to never smoke, or to quit. Smoking raises the risk of lung cancer 20-fold, he pointed out.
"But another good way to reduce the risk is through screening," he added.
Barry urged current and former smokers to ask their doctors whether they should be screened.
The USPSTF recommendations are in the "draft" stage and will be available for public comment until Aug. 3 at uspreventiveservicestaskforce.org.
The American Lung Association has more on lung cancer screening.