Lung lesions can be tested less invasively, study finds

When a suspicious lesion shows up in the lungs on a CT scan, the first thing your doctor wants to know is whether it is cancerous. A specialist will pass a long, thin bronchoscope into your airway in the hope of grabbing a few cells of the growth so they can be examined under a microscope.

But some of these lesions or nodules are deep in the small branches of the lungs, out of reach of the bronchoscope, which is about the diameter of a pen. Other times, the results are inconclusive. That has left only two ways to determine whether the abnormality is cancerous: inserting a needle through the chest wall and into the tumor, or surgically opening a patient's chest to find it — and remove it if necessary.

But now, according to a study published Sunday in the New England Journal of Medicine, there appears to be a new, much less invasive way of determining whether a growth is malignant. Researchers at Boston University have discovered that the thin epithelial cells that line the entire airway show changes that indicate whether a growth is malignant. With small brushes on the bronchoscope, doctors can take some of those cells and, using genomic testing that has been available only in recent years, reach a conclusion.

The study showed that the tests were about 97 percent accurate on 639 subjects. A private company has purchased the technology and is making it available to hospitals across the country.

"Even though lung cancer tends to develop deep in your lung, all the cells that line your airway are exposed," said Avrum Spira, a professor of medicine at Boston University who led the research. "They have changes in their genome."

Spira's test focuses on messenger RNA, the molecules that express genes' instructions to cells. He called the technology "a canary in the coal mine" for lung cancer.

If the test is negative, its accuracy will allow doctors to wait and watch a lesion. If it shows a malignancy, a biopsy still would be needed to confirm the cancer. "There will still be a small number of biopsies," Spira said. "But we're going to reduce them significantly."