van Keulen KE, et al. - Researchers examined whether exhaled volatile organic compounds (VOCs) could help in detecting colorectal cancer (CRC) and precursor lesions using an electronic nose. In this multicentre study, they collected 511 breath samples. Of these, exclusion was done of 64 patients due to an inadequate breath test (n = 51), incomplete colonoscopy (n = 8) or colitis (n = 5). Training models were developed using two-thirds of the breath tests; these models were then utilized to predict the diagnosis of the remaining patients (external validation). In the end, final-disease models were developed using all data to further improve the discriminatory power of the algorithms. Based on the most advanced lesion found, they performed classification; CRC (n = 70), advanced adenomas (AAs) (n = 117), non-advanced adenoma (n = 117), hyperplastic polyp (n = 15), normal colonoscopy (n = 125). For CRC and AAs, training models had an area under the curve (AUC) of 0.76 and 0.71 and blind validation produced an AUC of 0.74 and 0.61, respectively. Final models produced an AUC of 0.84 (sensitivity 95% and specificity 64%) and 0.73 (sensitivity and specificity 79% and 59%) for CRC and AAs, respectively. Findings support the potential utility of exhaled VOCs as a non-invasive biomarker for the detection of CRC and AAs.