Analytical and unconventional methods of cancer detection using odor

Finding a non-invasive, painless and simple screening method for early detection of cancer is a desirable goal. There is evidence that volatile organic compounds (VOCs) detectable in exhaled air and producing specific breath odor could be taken into consideration as possible cancer markers. Chemical analysis of VOCs in the breath that utilizes gas chromatography-mass spectrometry or an array of specific sensors (an electronic nose) could be useful for cancer screening. Preliminary reports show that canines, due to their extraordinary sense of smell and ability to perform well with operant conditioning, could also be used in the future as biological screeners for different forms of cancer. However, the question remains open whether specific VOCs or breath odors appear at very early (sub-clinical) stages of cancer disease or only at advanced stages of the disease during tumor decomposition.