WASHINGTON — Annual CT scans of current and former heavy smokers reduce the risk that they will die from lung cancer by 20 percent, a huge government-financed study has found.
Even more surprising, the scans seemed to reduce their risk of death from other causes as well.
The finding, announced by the National Cancer Institute on Thursday, represents a major advance in cancer detection that could potentially save thousands of lives annually, although at considerable expense. Lung cancer claims about 160,000 lives each year, more than the deaths from colorectal, breast, pancreatic and prostate cancers combined. In most patients, the disease is discovered too late for effective treatment, and 85 percent of those who are diagnosed with lung cancer die from it.
Until now, no screening method had proven to be effective at reducing mortality from the disease. Four randomized, controlled trials done during the 1970s showed that chest X-rays helped to catch cancers at an earlier stage, but had no effect on overall death rates. Since then, researchers have suggested that CT scans — which use coordinated X-rays to provide three-dimensional views of body tissue — could detect lung tumors at an even earlier stage than X-rays could, but no trial had shown conclusively that deaths could be averted.