Metabolomic-based tests for colorectal cancer
For an individual aged 50–74 years without a family or personal history of colorectal cancer, current population-based screening tools consist of a combination of a stool tests and/or a diagnostic imaging study. If colonic polyps are identified, these are then removed via colonoscopy. Each of these tests and combinations have advantages and limitations, the most important of which is the well-documented limited compliance with stool testing by individuals in addition to its limited diagnostic sensitivity. More recently, the concept of using a blood or urine metabolomics test to replace the stool test for detecting colonic polyps or cancer has been introduced and discussed in the literature . Needless to say, blood and urine would significantly increase the compliance of screening for this common malignancy as they are less messy to collect than stool samples. Metabolomics is the study of the byproducts of metabolism and has great potential for biomarker discovery as it provides a snapshot of what has already happened in the body as opposed to what is predicted to happen. Uniquely, metabolomics can also capture discrete biochemical changes in the body during initial perturbations in health before the development of clinical symptoms. The problem with currently used fecal-based testing is that it relies on the detection of heme or globin in the stool; however, most polyps, the precursor of colon cancer, do not bleed.
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