CT Screening Finds Lung Cancers Early
85% of Cancers Found in Study Were More Survivable Stage 1 Type
Another concern about CT scanning is that it could result in the diagnosis and treatment of tumors that would never become life-threatening.
Overdiagnosis is impossible to document in living patients, but autopsy studies have shown undetected lung cancers in many people who died of other causes.
The I-ELCAP results appear to address this concern. Eight of the study participants whose stage I cancers were first identified through CT scanning were not treated, and all eight died within five years of diagnosis.
The NCI is conducting its own study to compare CT scanning to traditional chest X-ray for the early detection of lung cancerlung cancer.
The aim of the study, which includes 52,000 current smokers or former smokers, is to determine if regular screening with either test reduces deaths from the disease.
Results from the trial are expected by 2009, but Gary Kelloff, MD, of the NCI, tells WebMD they could come sooner if clear trends are seen before then.
"We still don't know if we are reducing lung cancercancer mortality in a screened population," he says. "The I-ELCAP trial was well done and it certainly adds to what we know. But we still have a lot to learn."
Kelloff is special advisor to the NCI's Cancer Imaging Program, in the Division of Cancer Treatment and Diagnosis.
American Cancer Society Director of Screening Robert Smith, PhD, says the I-ELCAP study proves that a specific CT scanning model can be duplicated in different settings and that false-positive findings can be minimized with strict adherence to a rigorous screening protocol.
"These are very exciting findings that show real promise for reducing this country's top cause of cancer death," he says. "But health policy isn't made on the basis of one study, or by one organization."
Smith adds that the ongoing NCI lung cancer trial should answer many questions about the benefits vs. risks of lung cancer screening.
In the meantime, he says, people at risk for lung cancer who are considering CT screening should discuss the matter with their doctor.
Smith also recommends choosing a testing site with experience in lung scanning.