CHICAGO -- Lung cancer screening rates remain low across the U.S., despite evidence that the tests can save lives, a researcher said.
Based on , the U.S. Preventive Services Task Force in 2013 recommended that high-risk smokers get tested annually using low-dose computed tomography (LDCT), according to Danh Pham, MD, of the James Graham Brown Cancer Center at the University of Louisville in Kentucky.
But the first analysis of screening rates since those recommendations were issued shows they're having a very limited effect, Pham said at a press briefing prior to the annual meeting, where the study will be presented next month.
"Annual low-dose CT screening ... remains inadequate," Pham said, adding the analysis is "a call to arms to increase much-needed screening."
The National Lung Screening Trial was stopped early in 2010 when it became clear that -- among high-risk smokers -- annual screening using LDCT reduced death from lung cancer by 20% compared with chest x-ray.
It was the first time a large, randomized controlled trial had found a benefit for lung cancer screening, and it led to USPSTF guidelines that urged doctors to test patients annually if they are 55 through 79 and:
- Have a 30 pack-year history of smoking
- Either still smoke or who have quit within the previous 15 years
Medicare later agreed to pay for the annual testing in most of those patients.
But it has not been clear how well those recommendations have been followed, Pham said. To find out, he and colleagues turned to the American College of Radiology's Lung Cancer Screening Registry.
The registry contains data from all 1,796 accredited radiographic sites in the U.S.; Pham and colleagues compared the information to the estimated number of eligible patients, using the findings of the National Health Interview Survey.
To get screening rates, they divided actual tests in 2016 by the estimated number of eligible patients in the four U.S. census regions -- Northeast, South, Midwest, and West. They found:
- The highest rate was in the Northeast, at 3.5% and the lowest in the West, at 1.0%
- The Midwest had a rate of 1.9% and the South saw 1.6% of eligible patients tested
The proportion of eligible smokers was highest in the South and lowest in the West and Northeast, he said.
Across the country, there were an estimated 7,612,975 people who met the criteria for testing and 141,260 tests were performed, for a national screening rate of 1.9%, Pham said.
That rate is inadequate, Pham said, especially when compared with other cancer screening rates. For instance, he noted, about 65% of women 40 or older had a mammogram in 2015.
He added the shortfall could arise in two ways -- doctors might not be referring patients or the patients themselves might not want to undergo the testing. There is, Pham said, still some controversy among providers about the value of LDCT screening and it's possible that some patients feel stigmatized for a poor lifestyle choice if they get the test.
Lung cancer remains a major killer, with an estimated 154,040 deaths projected for 2018, Pham said. Higher screening rates could prevent up to 12,000 of those deaths a year, he concluded.
ASCO President Bruce Johnson, MD, said the finding is "disappointing," but cautioned that the study is a snapshot of the first year after all the pieces were in place -- evidence, recommendations, and Medicare payments -- and might not represent a "steady state" of screening.
But he echoed Pham's call to arms: Lung cancer doctors, he said, "would like to be put out of business by an effective screening program."