Newly crunched big data show that very few people at high risk for lung cancer from smoking benefit by getting annual low-dose CT screenings after an initial exam brings back negative results, according to a study published online March 21 in The Lancet Oncology.
Using data from the National Lung Screening Trial, Duke University’s Edward Patz Jr., MD, and colleagues looked at 19,066 patients with a history of 30 pack-years whose initial LDCT screening showed no cancer.
The researchers found that just 2 percent (444 patients) had lung cancer at their most recent follow-up.
Only 17 of the initial-negative LCDT patients, 0.09 percent, were diagnosed with cancer in the months prior to their first scheduled annual screen, while 75 patients (0.4 percent) were diagnosed with lung cancer between the first and second annual screening.
Patz and team estimated that, if the first annual screen had been skipped in the initial-negative group, an additional 28 participants in that group might have died of lung cancer.
This “at-most” scenario came from calculating a rise in mortality from 186 vs. 212 deaths per 100,000 person-years over the course of the study.
“Participants with a negative low-dose CT prevalence screen had a lower incidence of lung cancer and lung cancer-specific mortality than did all participants who underwent a prevalence screen,” the team concluded. “Because overly frequent screening has associated harms, increasing the interval between screens in participants with a negative low-dose CT prevalence screen might be warranted.”
In a press release from Duke publicizing the work, Patz put it in more direct terms.
“Not screening patients annually,” he said, “could save millions in healthcare costs and spare patients the radiation exposure and the downstream effects of false positive screenings.”