When a suspicious lesion shows up in the lungs on a CT scan, the first thing your doctor wants to know is whether it's cancerous. But some of these lesions or nodules are deep in the small branches of the lungs, out of reach of the bronchoscope, reports The Washington Post. 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 tumour, or surgically opening a patient's chest to find it (and remove it if necessary).
The first procedure carries a 15% risk of collapsing a lung (pneumothorax), as well as infection. The second is serious surgery that requires general anaesthesia and results in the loss of lung tissue. Both are in-patient procedures that carry the cost and other risks of hospitalisations. In about a third of the surgeries, the growth turns out to be benign, meaning the surgery was unnecessary.
But now, according to a study, 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, they can take some of those cells and, using genomic testing that has been available only in recent years, reach a conclusion.
The report says the study showed that the tests were about 97% 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. 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."
Other research is being conducted to find markers for lung cancer, though much of it focuses on substances that can be found in the blood, Spira said. With the vast majority of lung cancer victims being smokers, the epithelial cells show changes that could be tracked once the technology became available, he said.
The next logical question is whether those changes might be detected early enough to predict and prevent lung cancer. Spira said his team already is working on research to determine whether that's possible.
[link url="http://www.washingtonpost.com/news/to-your-health/wp/2015/05/17/new-test-could-sharply-reduce-risky-costly-lung-cancer-biopsies/"]Full report in The Washington Post[/link]
[link url="http://www.nejm.org/doi/full/10.1056/NEJMoa1504601#t=articleTop"]New England Journal of Medicine article[/link]