Lung Cancer CT Scans No Help?
CT Scans for Smokers Up Risks, Don't Cut Lung Cancer Deaths, Study Shows
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
The patients in their study had gotten CT scans before they had any sign of
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
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
"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
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
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.