Exhaled breath analysis: novel approach for early detection of lung cancer

Lung cancer is a leading cause of cancer death, with the prognosis adversely affected by late diagnosis. Early diagnosis of lung cancer is desirable, but current evidence does not support the application of screening with techniques such as chest radiography, sputum cytology or computed tomography. Breath analysis, which includes gaseous phase analysis that measures volatile organic compounds using electronic noses, exhaled nitric oxide, and exhaled breath condensate (EBC), has been proposed as a non-invasive and simple technique to investigate neoplastic processes in the airways. EBC can be easily collected by breathing into a cooling system that condenses the water vapour in the breath. EBC has already been demonstrated to be useful in investigating inflammatory and oxidative stress changes in various respiratory conditions as it contains measurable mediators of airway inflammation and oxidative stress markers. Furthermore, EBC has also been shown to be a useful method to monitor severity of diseases such as asthma and to act as a surrogate measure of compliance to medical therapy. Presently, there still remains a relative paucity of lung cancer research involving EBC. However, since EBC is a simple, non-invasive technique that can be easily performed, even in ill patients, it has the potential to be validated for use in screening for the early diagnosis of lung cancer.