Detection of gas components as a novel diagnostic method for colorectal cancer

Background The fecal occult blood test (FOBT) is widely accepted as the most economic and non‐invasive screening method for colorectal cancer (CRC). However, the FOBT is inconvenient because it requires a fecal sample and shows limited accuracy. Alternatively, we hypothesized that fecal gas compounds from bowel movements may be a non‐invasive biomarker for CRC. Methods Gas compounds were collected from the bowel movements of 30 patients with CRC and from 26 healthy controls. The patient group comprised 17 males and 13 females, and the average age was 68 years. Additionally, 22 patients had colon cancer, and eight patients had rectal cancer. Gas compounds were analyzed using gas chromatography and compared with those from healthy controls. Results In the gas analysis, methyl mercaptan was significantly higher in the CRC group than in the control group. Hydrogen was significantly lower in the CRC group than in the control group and was correlated with tumor depth and advanced disease stage. Sensitivity, specificity, and accuracy of detection by a discriminant formula were 90%, 57.7%, and 75%, respectively. Conclusion Gas compounds from defecation constitute a promising, novel non‐invasive approach for CRC screening. (UMIN000028256)
This study analyzed the gas compounds of colorectal cancer (CRC) patients and healthy controls at defecation in toilet using an extremely non‐invasive technique. The volatile organic compounds from defecation are different compared with CRC patients and healthy controls. The sensitivity, specificity, and accuracy of the discriminant formula for colorectal cancer were 90%, 57.7%, and 75%, respectively. We concluded that gas compounds from defecation constitute a promising, novel non‐invasive approach for CRC screening.