A breath test that analyzes volatile organic compounds to detect esophagogastric cancer showed similar diagnostic accuracy to an existing test for endoscopy referral based on clinical parameters, based on a study in 335 patients – 163 with esophagogastric cancer and 172 controls.
The resulting test, which examined the concentrations of volatile organic compounds including butyric acid, hexanoic acid, butanal, and decanal, had a sensitivity of 80%, a specificity of 81%, and an area under the curve of 0.85. However, all of the patients had T3-stage esophagogastric cancer, so there is no indication about whether the breath test would be effective at picking up earlier T1-stage cancers, the authors wrote in the study, published online May 17 in JAMA Oncology.
By comparison, the clinical parameters test based on the NICE guidelines for endoscopy referral has a sensitivity of 59%, a specificity of 81% and an area under the curve of 0.72. These guidelines use age thresholds and symptom criteria such as dyspepsia, but the authors commented that there still remains a huge degree of variability in referral patterns for endoscopy.
“The breath test for esophagogastric cancer aims to provide clinicians with an objective assessment of need for endoscopic referral,” wrote Sheraz R. Markar, PhD, of the department of surgery & cancer at Imperial College London and his coauthors.
The authors said the diagnostic accuracy of the breath test also compared favorably with other cancer diagnostic technologies such as the fecal occult blood test – for which the sensitivity ranges from 30% to 70% – and the Cytosponge test for Barrett esophagus, which has a sensitivity of 73%.
Because all five volatile organic compounds showed an association with esophagogastric cancer, the authors suggested that there could be the possibility of calculating a more stratified risk of cancer for individual patients.
The study found no significant differences in the concentration of the five volatile organic compounds used in the test between patients with esophageal or those with gastric cancer.