SUNDAY, Nov. 12, 2006 (HealthDay News) -- A simple breath test could someday help predict who's at highest risk of getting lung cancer.
In preliminary research, the breath test was successful in finding cancer "markers," said senior researcher Dr. Simon D. Spivack, a pulmonologist at the Wadsworth Center, the public health laboratory of the New York State Department of Health.
That's important, he added, because "lung cancer [typically] exists for a decade or two before it is diagnosed."
His team was expected to present the results Sunday at the American Association for Cancer Research meeting in Boston.
Lung cancer remains the No. 1 cancer killer of both men and women in the United States. According to the American Lung Association, over 160,000 Americans die of the disease each year.
One reason for the high death toll: About 70 percent of lung cancers are diagnosed in the late stages, according to the Lung Cancer Alliance, a national advocacy organization based in Washington, D.C. However, one recent study found that, if diagnosed early, 92 percent of patients could expect to live 10 years.
Doctors have long sought a reliable early detection method. Even when something that looks like a predictor of cancer is found -- such as a nodule on the lung during a CT scan -- it's still not a foolproof way to determine who will get cancer, Spivack said.
"What we find in middle-age smokers is that 20 to 80 percent of these people have nodules," he said. "But 95 percent of the nodules are not cancer and are not going to be."
Enter the new test, in which people are asked to breathe for 10 minutes into a commercially available device which cools the air and forms a condensed vapor. Next, the researchers apply an assay that detects chemical changes -- specifically, a DNA methylated form of a tumor-suppressor genes.
In the test, "exhaled breath DNA could be measured for methylation, a known cancer marker," Spivack said.
DNA methylation is a kind of chemical modification of the cell's DNA, a process known to be associated with lung and other cancers.
To date, Spivack's team has used the tool on 28 people, predominately cancer-free smokers, and they are still analyzing the results for 21. Spivack currently has results for 7 people. He found that "in one gene, smokers were methylated and nonsmokers were not." He is looking at six genes in all and is still analyzing the results.
"This tool may or may not be helpful in diagnosing disease at the present time," Spivack said. "This tool aims to assess risk, so we know how to follow these people." For instance, someone deemed at high risk could be scheduled for more frequent check-ups.
Nicholas Broffman, executive director of the Pine Street Foundation, a San Francisco area-based nonprofit charity that helps people with cancer make informed decisions about treatment, said the study was "interesting."
The Foundation made news earlier this year with its study on how dogs could pick up chemical differences lingering in the breath of persons with cancer. That work was published in the journal Integrative Cancer Therapies
When the dogs sniffed the breath of 55 patients with lung cancer, 31 with breast cancer, and 83 healthy people, the animals were 88 percent to 97 percent accurate in identifying early- and late-stage breast and lung cancers.
"We are just scratching the surface of breath diagnostics," Broffman said. Worldwide, he said, the number of researchers investigating breath analysis for cancer is not as large as it could be. "I would hope more people would get into the game," he said.
Broffman said Spivack's method "is a really interesting technique because it is not invasive."
More information
To learn more about lung cancer, visit the Lung Cancer Alliance.
