Catching wind of non-invasive biomarkers for inflammatory bowel disease and colorectal cancer

This summary is part of 'Chapter 16: Summary and general discussion' This thesis focused on the exploration and development of non-invasive biomarkers for the detection and follow-up of inflammatory bowel disease and colorectal neoplasia, based on faecal metabolic end-products of pathophysiological pathways. These end-products include faecal bacterial composition (microbiota), protein spectra (proteomics) as well as metabolite spectra (metabolomics), in specific amino acid profiles and faecal volatile organic compounds (VOC), which are referred to as ‘omics’ platforms. Throughout this thesis, deep phenotyping of study participants based on these omics strategies has led to the exploration of potential tools for novel, accurate and non-invasive disease detection, surveillance and prediction of disease course at an early stage. This thesis highlights the potential of faecal VOC analysis for the detection of IBD and the prediction of its disease course. In addition, its potential for CRC and adenoma detection is presented and proposed to be a reliable tool for intra-individual surveillance and to estimate the timing endoscopy after polyp removal. We have described combined omics panels to increase diagnostic accuracy for detection of both CRC and adenomas compared to the use of solely one omics platform. Future studies should focus on the following aspects: a standardized method for VOC measurements, robustness assessment of amino acid profiles, a prospective validation study comparing all biomarkers and algorithms to the gold standard and a cost/benefit assessment. This way the best biomarker(s) and/or algorithms may be selected for further development as clinical tools, improving detection of disease at an early stage which subsequently leads to earlier treatment, lower numbers of complications, surgery, hospital admission and eventually morbidity.