Breath test can indicate lung cancer
An analysis of breath samples from patients with pulmonary nodules distinguished benign from malignant growths in a recent study.
Previous research has shown that theoretically, lung cancer can be detected through noninvasive exhaled-breath analysis. To further evaluate the potential of this practice, an investigative team launched a prospective trial in which breath samples were taken from 72 persons with pulmonary nodules. The researchers combined gas chromatography/mass spectrometry (GC-MS) with solid-phase microextraction and a chemical nanoarray to profile volatile organic compounds in the breath. Final diagnosis was made with bronchoscopy, wedge resection, and/or lobectomy.
GC-MS analysis identified a significantly higher concentration of the chemical 1-octene in the breath of persons found to have lung cancer. The nanoarray distinguished significantly between benign and malignant pulmonary nodules, between adenocarcinomas and squamous cell carcinomas, and between early-stage disease and advanced disease.
A total of 53 pulmonary nodules were accurately identified as malignant (mean size 2.7 cm) and 19 were benign (mean size 1.6 cm). In the malignant group, 47 nodules were non-small cell lung cancer, and 6 were small cell lung cancer. Thirty patients had early-stage disease and 23 had advanced disease.
As explained in a statement from the International Association for the Study of Lung Cancer, which publishes Journal of Thoracic Oncology, where the breath-analysis trial results appear (2012;7:1528-1533), low-dose computed tomography (CT) screening for lung cancer has reduced the disease's mortality rate by 20%, but many patients screened by CT have to undergo invasive procedures only to find that their pulmonary nodules are not cancerous. (The false-positive rate is 96%.) Breath testing could serve as a secondary screener for persons who were found to have pulmonary nodules on CT screening.
The investigators conclude that although further studies are required to validate this noninvasive approach, breath testing could have a significant impact on reducing unnecessary evaluation, the risk of procedure-related morbidity, and costs. In addition, breath testing could lead to faster therapeutic intervention for patients.