The tiny, inexpensive sensor used to detect lung cancer.
Credit: Thorax
SYDNEY: A breath test can successfully pick up the early stages of lung cancer, according to a new U.S. study.
"This study could lead to an inexpensive, non-invasive screening or diagnostic tool for lung cancer," the authors wrote in a paper published in the international journal Thorax.
People with lung cancer breathe out a chemical signature - a unique pattern of volatile organic compounds caused by metabolic changes in cancer cells. According to the researchers, their breath test can detect tiny changes in this chemical signature using a colorimetric sensor array.
The sensor, which is about the size of a 10 cent piece, is made up of 36 spots of different chemically sensitive compounds impregnated on a disposable cartridge. The spots change colour depending on the chemicals they come into contact with, allowing doctors to quickly analyse results.
Led by Peter Mazzone of The Cleveland Clinic in Cleveland, Ohio, the researchers tested the gadget on 122 people with different types of respiratory disease and on 21 healthy people. The group included 49 people with lung cancer at various stages of development.
The research team used the sensor results from 70 per cent of the study participants to develop a predictive model - a colour pattern characteristic of lung cancer sufferers - the accuracy of which was then tested on the remaining 30 per cent.
The test was able to accurately predict the presence of the disease in almost three quarters of those with lung cancer, regardless of age, gender, or the stage of disease. Mazzone says his work is "proof of principle" that the new sensor is a useful clinical test, but adds that its accuracy has to be refined.
Lung cancer kills more than 7,000 Australians every year, about three times more than breast cancer, according to the Australian Institute of Health and Welfare. Diagnosis is currently an expensive process only possible in the late stages of the disease, when treatment is less successful, the researchers explained.
Scientists have been working on a breath test for cancer since 1985, using gas chromatography and mass spectrometry. But machines using these technologies are particularly expensive and doctors require advanced training in their use.
According to the researchers, there is potential for this simple, inexpensive test to be used to determine which patients require further testing with more established technologies.
At present, however, technology is being outperformed by canines, Mazzone says. In a 2006 study, dogs trained to distinguish the breath of patients with lung and breast cancer were found to be 99 per cent accurate.
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