Catch your breath: Tests of exhaled breath may help diagnose pulmonary nodules

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Breath testing could be used to discriminate between benign and malignant pulmonary nodules, according to a pilot study published in the October issue of the Journal of Thoracic Oncology.

The testing method developed and studied by researchers Hossam Haick, PhD, and colleagues from the Technion-Israel Institute of Technology in Haifa, Israel, could bypass some problems inherent with CT screening.

Haick and colleagues studied 74 patients who were under investigation for pulmonary nodules and attended a referral clinic located in Colorado between March 2009 and May 2010. Exhaled breath was collected from each patient and analyzed using gas chromatography with mass spectrometry and information from chemical nanoarrays. Final diagnosis was confirmed using bronchoscopy, wedge resection and/or lobectomy.

Both the gas chromatography and nanoarray testing methods were able to accurately identify 53 malignant pulmonary nodules. Another 19 nodules were shown correctly by the techniques to be benign, which for this study was defined as nodules that either regressed or remained stable over a 24-month period.

The nanoarrays technique also was shown to discriminate between adenocarcinoma and squamous cell carcinoma, and between early versus advanced disease.

Haick and colleagues wrote that, “the reported breath test in this study could have significant impact on reducing unnecessary investigation and reducing the risk of procedure-related morbidity and costs. In addition, it could facilitate faster therapeutic intervention, replacing time-consuming clinical follow-up that would eventually lead to the same intervention."

Breath testing could serve as a secondary screening test for patients found to have pulmonary nodules on CT. Low-dose CT screening reduces mortality rates by 20 percent, however, with a false positive rate of 96 percent, many patients undergo invasive procedures following CT screening only to find their pulmonary nodules are not cancerous.