[to top of second column]
"Clearly it saves lives," said Dr. Stephen Swensen of the Mayo Clinic, among the 33 sites that conducted the massive study. But, because it carries the burden of unnecessary tests and treatment, "society has to figure out if we can afford this."
"We want to make sure what we recommend is appropriate rather than everybody going out and asking for it," added Dr. Edward F. Patz Jr. of Duke University, who was on the committee that helped design and oversee the study.
The new trial enrolled people ages 55 to 74 who are or had been very heavy smokers, puffing at least 30 "pack-years," the equivalent of a pack a day for 30 years or two packs a day for 15 years. They had one scan a year -- either spiral CT or a standard chest X-ray -- for three years, and then had their health tracked.
NCI's Varmus stressed that the study provided no data on whether screening helped lighter or younger smokers.
There were risks. The CTs frequently mistake scar tissue from an old infection or some other benign lump for cancer, giving about 25 percent of the spiral CT recipients a false alarm. In an earlier Mayo Clinic study of spiral CTs, more than 70 percent had a false alarm, because that study monitored even smaller lung nodules that the newer study ignored, Swensen said.
Then there's the radiation question. The new study used low-dose spiral CTs, equivalent to the radiation from a mammogram. That's far lower than the radiation emitted by regular CT scans used to diagnose various medical conditions, but several times more than is emitted by a standard X-ray.
The NCI will analyze whether the radiation exposures from the three scans in this study changed a smoker's lifetime risk of other radiation-related cancers. Doses can be vary widely at different hospitals using different scanners, but any CTs used for screening should be low-dose, Swensen said.
Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
< Recent articles
Back to top
News | Sports | Business | Rural Review | Teaching & Learning | Home and Family | Tourism | Obituaries
Law & Courts |
Spiritual Life |
Health & Fitness |
Calendar | Letters to the Editor