Some lung tumors not lethal, study finds

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It s hard to imagine lung tumors to be non-lethal but according to a new study, one in five detected on a CT scan are so slow-growing, they would not affect a person during his or her lifetime, contrary to the general scientific (and popular) consensus previously thought.

Recently, the U.S. Preventative Services Task Force issued a recommendation that current and heavy smokers be annually screened for the disease. The decision remains challenged, as some studies have shown overscreening can lead to overdiagnosis and overtreatment of tumors that typically would not cause problems among patients.

The new study is an analysis of data from the National Lung Cancer Screening Trial National Cancer Institute. More than 53,000 people at high risk for lung cancer were followed for about six years. Although all tumors detected were cancerous, researchers determined almost 18 percent of tumors found would not develop symptoms nor become deadly.

Still, there is no way for doctors to detect which tumors would remain benign in any particular individual following a CT scan. When lung cancer is diagnosed after symptoms have already developed or if a tumor is detected during a chest x-ray, it is almost always too late for curative treatment, which is why the 5-year survival rate for lung cancer hovers around 5-10 percent. This may change if routine screening of high-risk people meaning long-time smokers is implemented. Until then, the approach to diagnosis and treatment of the disease is unlikely to change.

"I don't think this will shift recommendations at all," Edward F. Patz Jr., MD, of Duke University Medical Center, and colleagues told MedPageToday. "It's just part of this entire puzzle we're trying to piece together, how we can best offer a mass screening program as public policy."