MINNEAPOLIS - When it comes to lung cancer, early detection might not be such a blessing after all, according to study being released today by the Mayo Clinic and other centers.
The scientists found that devices called CT (computed tomography) scanners can, as expected, find lung cancers at a very early stage in people with a history of smoking. But they also found that the early diagnoses had no impact on the number of people dying of the disease.
In fact, the report suggests that early diagnosis may backfire on many people by exposing them to operations they don't need. "We could be doing more harm than good," said Dr. Stephen Swensen, a radiologist at the Mayo Clinic who co-authored the study.
The report, in today's Journal of the American Medical Association, is the latest in a series of contradictory findings about the usefulness of CT scans in fighting lung cancer.
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Last October, another team of scientists reported just the opposite: that low-dose CT screening could prevent up to 80 percent of lung cancer deaths.
But the newer study concluded that many of the early-stage lung tumors posed little or no threat to patients, possibly because they are slow-growing. They also found that 98 percent of the suspicious nodules found on the CT scans were harmless, Swensen said.
Many patients needed further tests and surgeries to rule out cancer.
Scientists say the study doesn't rule out the possibility that CT scans could help lung-cancer patients in the long term.
New test might help predict cancer
Scientists might be close to being able to predict who will develop lung cancer - a development that could prevent tens of thousands of deaths a year in the U.S. alone.
Using a molecular test called a microarray, a research team from Boston University has come up with an 80-gene "signature" that can identify lung cancer at a very early stage in smokers. More importantly, the team showed that it is possible to detect pre-cancerous changes in normal tissue.