What Urine VOCs Reveal About Cancer: A Systematic Review

Individual studies can be promising but fragile. To see whether urinary volatile compounds genuinely carry diagnostic signal, this 2021 systematic review pooled the published evidence and assessed its quality.

What the researchers did

The authors searched the major medical databases and extracted data from 13 studies, covering 1,266 participants (700 with a cancer diagnosis). The studies spanned prostate, gastrointestinal, bladder, lung and blood cancers, and used laboratory methods such as gas chromatography–mass spectrometry to identify the volatile organic compounds (VOCs) in urine. The review judged the overall body of work to be at low risk of bias and highly applicable.

What they found

• 48 urinary VOCs across 11 chemical classes showed high diagnostic performance, with reported sensitivity of 72–100% and specificity of 60–96%.
• Profiles were distinctive for each cancer type, with limited overlap — suggesting urine VOC patterns are organ-specific.
• Several compounds recurred across studies, including p-cresol, phenol, dimethyl disulfide and acetic acid — all products of gut-microbial fermentation.
• The reviewers flagged a key limitation: methods varied widely between labs, which hampered reproducibility.

Why it matters

The recurrence of gut-derived compounds — p-cresol and dimethyl disulfide in particular — is striking. These molecules are made by gut microbes, then travel from the gut into the bloodstream and out through the kidneys into urine. That overlap reinforces a central idea in gut-health science: stool and urine carry complementary chemical signals of what the microbiome is doing. This is published disease-detection research, not a consumer diagnostic, and the authors are clear that standardisation is still needed.

“Forty-eight urinary VOCs belonging to eleven chemical classes were identified with high diagnostic performance, and VOC profiles were distinctive for each cancer type with limited cross-over.”