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Volatile organic compounds may help diagnose colorectal cancer
Analyzing volatile organic compounds found in fecal samples could aid in the diagnosis of colorectal adenocarcinoma, according to research published in Alimentary Pharmacology & Therapeutics.
Chris Probert, MD, FRCP, FHEA, of the Institute of Translational Medicine in Liverpool, United Kingdom, and colleagues wrote that previous studies have explored the potential of volatile organic compounds as biomarkers for CRC, but they have mostly been proof of concept studies that did not identify specific compounds.
“Therefore, understanding the biological plausibility for patterns of volatile organic compounds can be difficult to interpret,” they wrote. “We undertook a prospective study of the volatile organic compounds emitted from fecal samples obtained from patients at risk of colorectal cancer.”
Researchers collected fecal samples from 137 symptomatic patients and individuals participating in the U.K. Bowel Cancer Screening Program (54% male; mean age 64 years). Sixty patients had no neoplasia, 56 had adenomatous polyps and 21 had adenocarcinoma. Investigators identified organic compounds using headspace extraction followed by gas chromatography mass spectrometry, and tested potential biomarkers using regression modeling and 10-fold cross-validation.
In their analysis, Probert and colleagues determined that propan-2-ol was significantly more abundant in the cancer samples (P < .0001) with an under ROC of 0.76. When propan-2-ol was found along with 3-methalbutanoic, the area under ROC was 0.82 with a sensitivity of 87.9% (95% CI, 0.87–0.99) and specificity of 84.6% (95% CI, 0.65–1). Researchers found that a three-compounds panel that included propan-2-ol, hexan-2-one and ethyl 3-methyl-butanoate had an area under the ROC of 0.73, and if an individual’s sample had all three compounds, they were six times more likely to have cancer (P < .0001).
Probert and colleagues wrote that bacterial metabolites are likely the source of the volatile organic compounds linked to CRC, but more research is needed to determine the precise sources.
“Volatile organic compounds emitted from feces can be utilized as a biomarker for colorectal cancer,” they concluded. “Prospective studies are required to determine whether volatile organic compounds are better than FIT testing or whether they should be used together.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.