Pooling the Evidence: How Well Can Gut and Breath Gases Detect Colorectal Cancer?

Individual studies on reading the body’s gases are intriguing, but the strongest evidence comes from combining many of them. This 2024 systematic review and meta-analysis did exactly that, pooling the published research to ask how accurately volatile-compound analysis and electronic-nose sensors can detect colorectal cancer.

What the researchers did

The authors searched the major scientific databases through September 2023 and gathered 32 qualifying studies covering 4,688 people in total. These studies used a range of approaches — laboratory gas analysis and sensor-array “electronic noses,” applied to breath, stool and urine samples. The team then used statistical methods to calculate overall accuracy across all the studies combined.

What they found

• Volatile-compound analysis: pooled sensitivity of 0.88 and specificity of 0.85 for detecting colorectal cancer.
• Electronic-nose sensors: pooled sensitivity of 0.87 and specificity of 0.78 — nearly matching the full laboratory methods.
• Both approaches reached clinically meaningful accuracy, with sensor devices showing somewhat more variation across different study setups.

“Both VOC analysis and electronic nose technology demonstrate clinically meaningful diagnostic performance for the non-invasive detection of colorectal cancer.”

This is published research summarized for education, not medical advice — no consumer product diagnoses cancer. For understanding gut health more broadly, the message is clear and well-backed: the gases produced by the body carry genuine, measurable signals about what is happening inside, and even compact sensors can read a meaningful part of that signal. It is a strong foundation for the science of listening to the gut through its chemistry.