Docs Nix Lung Scan
Feb. 22, 2002 -- It's now possible to detect lung cancer earlier than ever before. The downside: too many false alarms make lung-cancer screening too painful and costly.
The new technology is called low-dose spiral computed tomography or CT. It's a great tool. Doctors would love to be able to use it for lung cancer screening. Why? New screening tools for breast, colon, and prostate cancer have increased survival over the last 25 years. Yet there's been no improvement in lung-cancer survival.
By the time lung cancer is discovered, it's already too late for three out of four patients to be cured. Could fancy CT scans improve this grim statistic? A group of Mayo Clinic researchers tried to find out. For two years they gave spiral CT scans to 1,520 people age 50 or older who were long-time pack-a-day cigarette smokers.
The results appear in the current issue of the American Journal of Respiratory and Critical Care Medicine. More than two-thirds of the people in the study learned that they had suspicious nodules in their lungs.
"We estimate that 98% of these are falsely positive findings," study leader Stephen J. Swensen, MD, says in a news release. The authors note that nearly all high-risk patients would be expected to have at least one false-positive finding after just a few years of screening.
CT screening did find 25 lung cancers, and 22 of them were potentially curable. That's a vastly better possible-cure rate than would be expected in cancers found during routine exams. But another seven patients had surgery to remove what turned out to be benign lesions.
CT screening also missed lung nodules in more than one out of four patients.
Swensen and co-workers conclude that CT screening could possibly decrease lung-cancer deaths. But they note that the "very high" rate of false alarms makes CT screening "prohibitively expensive" in terms of financial and emotional costs.