Non-invasive volatile organic compound analysis from exhaled breath for the diagnosis of gastroesophageal cancer.

Abstract

TPS225 Background: The work carried out in our laboratory using Selective Ion Flow-Tube Mass Spectrometry (SIFT-MS) analysis of volatile organic compounds (VOCs) in exhaled breath has identified compounds that can differentiate gastro-esophageal cancer from non-cancer patients. A model has been developed based on 220 patients with upper gastrointestinal pathology (81 cancer, 88 positive control and 51 patients with endoscopically normal gastrointestinal tract). Methods: Clinical trial registry number: 14/LO/1136. Study 1: Refinement of VOC exhaled breath model. Exhaled breath from 120 patients undergoing diagnostic lower endoscopy for the investigation of gastrointestinal symptoms will be used to refine the existing model by studying the influence of lower gastrointestinal diseases and in particular colorectal cancer, upon VOC analysis. To date 94 patients have been recruited. Study 2: Blinded validation multi-centre study for the use of exhaled Breath SIFT-MS analysis to predict gastro-esophageal cancer. This study will be conducted across four centers and will utilize SIFT-MS exhaled breath analysis, for comparison of predicted cancer risk based upon the VOC exhaled breath model compared to endoscopic findings and histology biopsies in order to determine the overall diagnostic accuracy for this non-invasive test. Sample Size – Based upon a prevalence of cancer of 50% in the study population and maintaining a sensitivity and specificity of 80% for the diagnostic model derived from our previous research, the sample size estimated is 325 patients. Inclusion criteria:Patients with upper gastrointestinal symptoms attending for endoscopy or surgery. Exclusion criteria: Patients with a documented active infection or liver disease. Statistical methods: Comparison of predicted cancer risk and actual OGD findings or histology from endoscopic biopsies will then be made, and the overall diagnostic accuracy (sensitivity, specificity, positive and negative predictive value, ROC curve analysis) for this non-invasive diagnostic investigation will be determined. Deliverables: The diagnostic accuracy of the exhaled breath test for the prediction of oesophago-gastric cancer. Clinical trial information: 14/LO/1136.