A simple breath test for lung cancer got a step closer to reality today with research showing that specific compounds in the breath can indicate the presence or absence of lung cancer. Findings presented to the Society of Thoracic Surgeons 50th annual meeting showed that high-tech sensors can detect specific compounds in the breath released by lung cancer cells.
Michael Bousamra, M.D. and a team of researchers from the University of Louisville developed a silicone microprocessor and mass spectrometer that showed 95-percent accuracy in detecting specific volatile organic compounds (VOCs) associated with lung cancer. Called carbonyls, and more specifically aldehydes and ketones, these compounds produced by the body and can present a type of metabolic signature for lung cancer and other types of cancer.
Bousamra and colleagues gave the breath test to patients who already had suspicious tumors that had been detected by CT scans. Then they matched the breathalyzer findings with biopsy and clinical data. For patients whose breath contained elevated levels of three or four VOCs associated with cancer, the breath test was 95 percent accurate in predicting their tumors would turn out to be malignant, the researchers said.
The opposite also proved true. When participants’ breath did not contain the cancer-specific carbonyls, the test was 80 percent accurate in predicting that their tumors would turn out to be benign.
The researchers cautioned that their data are preliminary and have yet to be published in a peer-reviewed journal. However, there’s ample evidence to support the idea that cancer cells release specific organic compounds in the breath that can indicate the presence of a tumor.
For example, in 2012, a team of researchers from the Winship Cancer Institute at Emory University presented findings to the American Society of Clinical Oncology (ASCO), published in the Journal of Clinical Oncology, showing that 75 specific VOCs were significantly different in the breath of patients with lung cancer vs. those who were cancer-free. The Emory University researchers employed a device developed by the Georgia Tech Research Institute.
Another study published in 2012 identified colon cancer with more than 80-percent accuracy using 15 previously identified VOCs.
In fact, the race to perfect and prove a breath test for cancer is on around the country, with numerous research teams working to identify cancer-specific patterns of VOCs and to develop devices sensitive enough to accurately measure their presence.
And no wonder. Lung cancer is the deadliest cancer of all, killing more people than breast, prostate and colon cancer combined, according to the American Lung Association. One of the primary reasons lung cancer is so deadly is that it’s typically caught at a late stage, when it’s already begun to spread, or metastasize. Stage I lung cancer has a 70-percent cure rate, but by stage III or later fewer than 25 percent of cases can be cured. Hence the importance of developing tests that can detect lung tumors early.
Mountain View, California-based Metabolomx may be the furthest along in the race to bring a cancer breath test to market. The company’s colorimetric sensor, which detects and measures VOCs using 36 different chemically reactive colorants, is being tested in trials at the Cleveland Clinic’s Respiratory Institute.
Using Metabolomx’s sensor technology, Peter Mazzone, MD, director of the Institute’s lung cancer program, published research and presented findings at the American College of Chest Physicians Annual Meeting (CHEST 2013) showing that VOCs in exhaled breath could provide a “metabolic biosignature” that was 75-percent accurate in identifying compounds associated with lung tumors.
Metabolomx reports that the company has launched new trials in partnership with the Cleveland Clinic using a next-generation sensor that’s 100 times more accurate.
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