Since 2012, when the first study on the correlation between volatile organic compounds (VOCs) and colon cancer was published, the situation has changed a lot: research has been internationalized and diversified, and ways of collecting and analyzing the exhaled breath have changed. At the same time, we have come to realize how long a path there is still ahead, which, in order to reach our goal, essentially needs many more trial patients. To date, the exhaled breath of about 50 patients has been collected and analyzed, not a sufficient sample for drawing significant evidence.
Identifying patterns of molecules that indicate a tumor pathology is not simple. It can be influenced by variables such as the type of sampling performed, the analytical platform, possible environmental contamination or factors linked to other pre-existing diseases in the patient: this is why identifying a clear-cut protocol to follow is essential.
The sampling instrument is a critical tool in this sense, because it should help to exclude such misleading factors. The first sampler used, which was handcrafted, collected all the exhaled breath without special filters other than an external one that excluded the most important environmental VOCs. We then moved on to the Loccioni sampler, a higher-performing instrument because it is able to monitor CO2 and therefore only collect the alveolar fraction of the exhalation, decisive for diagnosis since the air coming from the alveoli is precisely that which reflects the passage of molecules from the blood to the respiratory system. However, in both devices, the exhaled breath is collected in bags of inert plastic material which, because they are not perfectly sealed, run the risk (albeit minimal) of allowing contamination. The subsequent steps – transferring the exhaled breath onto cartridges and then, through a thermal desiccator, into the gas chromatograph – further complicate the picture, making the process lengthy and therefore not suitable for a mass screening program.
The portable smart device now being worked on will eliminate these unfavorable elements: breathing for about four minutes in a controlled atmosphere will purify the exhaled breath of exogenous elements, the silica in the collection bag will then filter the sample further and block moisture, thus making the results more reliable as well as more rapidly available.
Clinical and technological research go hand in hand: firstly in articulating the know-how, and secondly in identifying the best tools. Identifying the patterns of molecules, as well as the stage in which the disease can be diagnosed by breath analysis, are key steps in arriving at a speedy diagnosis and with a considerably reduced stress load for the patient.