A new type of CT scan touted as a means of detecting lung cancer at its earliest stages is unproven, can lead to invasive testing and would probably not be cost-effective as a widespread screening tool, scientists say.
The so-called spiral CT scans involve scanners that view the lungs and surrounding tissue at various angles and can spot pea-sized growths. The scans have been heavily promoted over the Internet and on television.
But the new tests cost hundreds of dollars, are not covered by insurance and may lead to more diagnostic procedures such as surgery. Until solid data show they are beneficial, most people may want to hold off, researchers said in an analysis that appears today in the Journal of the American Medical Assn.
The scans are being evaluated in a recently launched National Cancer Institute study that compares them with standard chest X-rays. The results are not expected for several years.
Lung cancer, often diagnosed at advanced stages when it is incurable, has an average five-year survival rate of only 15%.
To analyze the cost-effectiveness of spiral CT scans, the researchers used a computer model of 100,000 hypothetical heavy smokers 60 and older, based on the data on real patients.
Using the model, the researchers calculated that there would be 4,168 lung-cancer deaths per 100,000 patients who did not get screened, versus 3,615 lung-cancer deaths among those who were screened.
While the screening cut deaths by 13%, there were also 1,186 invasive tests or operations for noncancerous lesions per 100,000 smokers screened.