The hot debate over lung cancer screening is the subject of the cover story in the May issue of Diagnostic Imaging. Senior editor James Brice examines whether this screening protocol delivers all it promises or whether it is better to wait and watch, even as mainstream media excitement continues to grow.
The benefits of the low-dose CT screening test for early detection of cancer in high-risk patients has become a matter of contention among researchers across the country, according to the story. The protocol, developed by the Early Lung Cancer Action Project (ELCAP), has received considerable media attention since last summer when the first reports were made public.
Sensing a ready market, some hospitals and medical centers have begun offering CT lung cancer screening directly to the public, a step that has researchers asking whether adoption of the screening protocol is premature and may do more harm than good.
If successful, CT screening could mean a dramatic decrease in lung cancer mortality. In the U.S. alone, 88 million smokers and former smokers are at high risk for lung cancer, according to the National Cancer Institute. The World Health Organization reports that the at-risk population is more than one billion worldwide. In the U.S., lung cancer kills more people than colon cancer, breast cancer, and prostate cancer combined.
Many radiologists and researchers are enthusiastic about low-dose CT screening. The early results are good, and the procedure is fast, fairly cheap, targeted to a specific at-risk population, and involves minimal radiation exposure. Moreover, nothing else in radiology's diagnostic armamentarium works.
Dr. Claudia I. Henschke, the lead ELCAP investigator and chief of chest imaging at Weill Medical College at Cornell University, received praise for developing the first promising screening test for lung cancer in years. But she has also drawn criticism for her aggressive advocacy of the procedure. While cautioning against premature community-based adoption, Henschke has actively promoted the test in the popular media.
"Our baseline data establish clearly that chest x-ray is not as good as a low-dose CT," Henschke said. "There is no question that patients diagnosed with early lung cancers have a better survival rate than patients with later lung cancer and that CT studies will improve the cure rate. Even if the improvement is only 10%, there would be a huge impact on the number of lives saved."
In clinical trials, 85% percent of early-stage cases not detected with radiography were detected with low-dose CT.
Among the critics of CT lung cancer screening are Dr. Edward Patz, a professor of radiology at Duke University. Despite results indicating that the ELCAP protocol finds cancers earlier than chest x-rays, it is premature to recommend screening, he said.
Before the true clinical utility of screening can be determined, a randomized trial is crucial to investigate the ELCAP protocol's effect on mortality, which is the ultimate measure of a screening exam's value, Patz said.
— By Monika Dhingra
For more on screening programs from the DI archives:
