SAN ANTONIO -- Adherence to annual lung cancer screening has been less than ideal among screening-eligible participants taking part in a Veteran's Administration Lung Cancer Screening Demonstration Project (LCSDP) researchers report.
In a retrospective study involving more than 2,000 veterans who had initial lung cancer screens, 22% of those with negative baseline screens eligible for additional screening failed to return for follow-up annual imaging, according to Paul Brasher, MD, of the Medical University of South Carolina and the Charleston VA Hospital, and colleagues.
"Our study demonstrates that even within the context of a well-designed, implemented, and guideline-adherent low-dose computed tomography (LDCT) screening program, adherence is not optimal and does not reach the reported 95% of the National Lung Cancer Screening Trial when the baseline scan is negative," Brasher said in a CHEST press release.
A total of 2,106 Veterans underwent a baseline LDCT across all sites. Some 60% had scans negative for nodules ≥4 mm in size and repeat annual LDCT was recommended.
In this group with a negative baseline scan, 149 were considered no longer eligible for screening because they had been diagnosed with lung cancer, were undergoing evaluation for cancer, no longer met the target age or years of cessation, were considered to have other life-limiting disease, or were no longer interested in participating.
Of the 1,120 remaining eligible for repeat annual LDCT, 870 went on to undergo the follow-up scan, yielding a 77.6% adherence rate after baseline screening.
As in the National Lung Screening Trial, adherence to screening was defined as having undergone a follow-up LDCT within 15 months from baseline scan.
In an interview with MedPage Today, Brasher said the finding suggests that achieving the 95% adherence rate for which lung cancer screening cost effectiveness and mortality benefit models are based will be a challenge in a real world setting.
He noted that in addition to receiving screening free of charge, the veterans participating in the LCSDP received three telephone calls and three letters reminding them about follow-up screening.
"Even in this academic hospital setting where patients aren't having to carry the burden of cost and there is an aggressive protocol in place to make sure people follow up, adherence wasn't optimal," he said.
He noted that the 95% expected adherence rate for lung cancer screening, based on the national screening trial experience, is much higher than the real-world adherence rate for breast, colon and other cancers, which average 40-65%.
The VA analysis included veterans screened at eight geographically diverse VA hospitals from July 2013 through June 2015. Baseline screening was performed in current or former smokers who had quit within the last 15 years, between the ages of 55 and 80 with at least a 30-pack year smoking history.
It is not clear from the study findings if follow-up screening adherence rates were better among participants with baseline screens that were not negative. Brasher and colleagues plan to examine this in future studies.
High adherence to repeat annual screening has been recognized by major health groups including the American College of Chest Physicians and the American Thoracic Society as necessary for high-quality screening programs.
"Screening data from other cancers tells us that key predictors of nonadherence -- such as being non-Caucasian, male, and having little healthcare -- are common among smokers," he said. "This suggests that this group might be especially hard to reach.
We also recognize that adherence is important, so we need to figure out what we can do to improve it in lung cancer screening."