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Lung Cancer CT Scans No Help?

CT Scans for Smokers Up Risks, Don't Cut Lung Cancer Deaths, Study Shows
By
WebMD Health News
Reviewed by Louise Chang, MD

March 6, 2007 -- CT scans that look for signs of early lung cancer don't seem to help current and former smokers avoid death, but they do increase the risk of unneeded surgery, biopsies, and radiation, a new study reports.

The finding comes from four years of follow-up data on 3,246 smokers and ex-smokers screened at medical centers in the U.S. and Italy.

It completely contradicts a study published last October, which seemed to find a huge benefit from CT screening for lung cancer.

Researchers Peter B. Bach, MD, of New York's Memorial Sloan-Kettering Cancer Center, and colleagues compared the actual number of advanced lung cancer cases and lung cancer deaths to the number predicted by a sophisticated computer model.

The patients in their study had gotten CT scans before they had any sign of lung cancer.

The scans led to 144 diagnosed cases of lung cancer, although the computer model predicted only 44.5 cases.

Of the 144 patients with scans positive for cancer, 109 underwent lung surgery.

But among all the screened patients, in the end 42 cases of advanced lung cancer were found -- compared to the 33.4 predicted by the computer.

And, despite the CT screening and subsequent treatment, virtually the same number of patients died as the computer predicted would have died without screening -- 38 of the screened patients, versus 38.8 predicted by the computer model.

"Patients should know two things about this study: First, nobody is more disappointed than we are," Bach tells WebMD. "And second, this is not the last word on the subject. There are two large clinical trials looking at this issue, one [funded by] the National Cancer Institute and the other in the Netherlands."

But the Bach team's findings are sobering, says William C. Black, MD, of Dartmouth-Hitchcock Medical Center in Lebanon, N.H. Black is co-author of an editorial published alongside the Bach study in the March 7 issue of The Journal of the American Medical Association. He's also an investigator in one of the clinical trials of CT lung cancer screening mentioned by Bach.

"The real bottom line is we simply don't know yet whether CT screening for lung cancer will cause more benefit than harm," Black tells WebMD. "We have two studies to date that show extremely conflicting results. Both have problems."

Big Risks From CT Screening for Lung Cancer

It's already been shown that using chest X-rays to screen symptom-free smokers for lung cancer does not result in fewer lung cancer deaths.

But researchers have been hoping CT scans would work better.

CT stands for computed tomography. It's a sophisticated, computer-assisted technique that gives doctors a much better look at an organ than an X-ray.

When used for screening, doctors set the CT scan to deliver only low-dose radiation. But that's still seven or eight times the radiation you'd get from an X-ray, Bach says.

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