Low-Dose CT Scans May Help Spot Early Lung Cancer
But expert notes questions about frequency remain
Each study participant got a low-dose CT scan, which was reviewed for the presence of nodules or other abnormalities that could suggest cancer. Those with nodules of 4 millimeters or larger or opacities (cloudy areas of tissue) were advised to get a biopsy.
Four people had lung cancer confirmed by biopsy, and one had a large mass but refused biopsy, reported study author Sue Yoon, a nurse practitioner in the pulmonary division at the Veterans Administration Boston Healthcare System.
While the new study found that 6 percent of the study participants had lung cancer, the earlier trial found only about 4 percent did, Yoon added.
Yoon noted there were significant differences between the two studies: Hers included many fewer people; scanning technology used in her study was more advanced than that used in the earlier research; and Yoon's patients were predominantly male and most had COPD.
Also, her study focused on finding evidence of cancer, rather than tracking cancer deaths, as the national screening trial did.
One of the issues concerning screening tests, including those for lung cancer, is that sometimes the test is inconclusive, noted Yoon. Many of the nodules detected are harmless, often the result of inflammation or scarring. "Our experience says it's good to have [a CT scan] but we don't know what the impact really is," she explained. After a lung nodule is found, some people don't like the idea of waiting a year and then having another scan.
"Some people worry so much they can't wait, and others, when we tell them they can wait a year to see what happens, they think they can still smoke since they don't have a big mass," she said.
But how often should people be scanned? "The current thought is that if you have a normal first exam, doing an annual exam would be satisfactory," Machnicki noted. "Whether or not longer intervals would be effective has not been tested."
Aggressive cancers may start and grow so quickly that they may be impossible to detect at a curable stage with any current technology, experts say.
Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.