Is the exhaled breath temperature in lung cancer influenced by airways neoangiogenesis or by inflammation?

Recently the exhaled breath temperature (EBT) was seen to increase in non-small cell lung cancer and was subsequently proposed as a possible non-invasive tool for its diagnosis. The need for further studies that confirm the previous findings and support the potential scope of this method underlies the main aim of this study that seeks to explore the pathogenic mechanisms determining the EBT in lung cancer. We enrolled 44 consecutive patients with a radiological suspicion of lung cancer and ten healthy non-smoker volunteers, after which their EBT was measured. On the same day, the subjects underwent breath condensate collection for the measurement of leukotriene (LTB)-4 and of the vascular endothelial growth factor (VEGF), the former being a marker of airways inflammation and the latter of neoangiogenesis. We confirmed the presence of a higher EBT in lung cancer patients compared to the controls. The multiple linear regression model showed that the exhaled VEGF was the only predictor of elevations of EBT. In conclusion, it can be stated that for the first time in this study, we have shown that EBT is higher in subjects with lung cancer and that the airways angiogenesis drives the increase in EBT in lung cancer. Moreover, the study suggests the potential for the use of EBT in monitoring the lung cancer progression, although the implementation of more in-depth studies to verify this result is recommended.