“The more we bring public awareness of this, then the more informed decisions might be when people decide to screen or not,” LeFevre said. He called the study “a very important contribution,” but said doctors will face a challenge in trying to explain the results to patients.
In testimonials, patients often say lung cancer screening via CT scans cured them, but the study suggests that in many cases, “we cured them of a disease we didn’t need to find in the first place,” LeFevre said.
The study was published Monday in the journal JAMA Internal Medicine.
More than 200,000 Americans are diagnosed with lung cancer each year, and more than half of them die. Worldwide, there are about 1.5 million lung cancer deaths annually.
The new study is an analysis of data from the National Lung Cancer Screening Trial — National Cancer Institute research involving 53,452 people at high risk for lung cancer who were followed for about six years.
Half of them got three annual low-dose CT scans — a type of X-ray that is much more sensitive than the ordinary variety — and half got three annual conventional chest X-rays. During six years of follow-up, 1,089 lung cancers were diagnosed in CT scan patients, versus 969 in those who got chest X-rays.
That would suggest CT scans are finding many early cases of lung cancer that may never advance to the point where they could be spotted on an ordinary chest X-ray.
An earlier report on the study found that 320 patients would need to get CT screening to prevent one lung cancer death.
The new analysis suggests that for every 10 lives saved by CT lung cancer screening, almost 14 people will have been diagnosed with a lung cancer that would never have caused any harm, said Dr. Len Lichtenfeld, the cancer society’s deputy chief medical officer.