Volatile organic compounds in bile can diagnose malignant biliary strictures in the setting of pancreatic cancer: a preliminary observation

Background: Ascertaining the nature of biliary strictures is challenging. The role of volatile organic compounds (VOCs) in bile in determining the cause of biliary strictures is not known. Objective: To identify potential VOCs in the headspaces (gas above the sample) of bile in patients with malignant biliary strictures from pancreatic cancer. Design: Prospective cross-sectional study. Setting: Referral center. Patients: Prospective study in which bile was aspirated in 96 patients undergoing ERCP for benign and malignant conditions. Main Outcome Measurements: Selected ion flow tube mass spectrometry (VOICE200R SIFT-MS instrument; Syft Technologies Ltd, Christchurch, New Zealand) was used to analyze the headspace and to build a predictive model for pancreatic cancer. Results: The headspaces from 96 bile samples were analyzed, including 24 from patients with pancreatic cancer and 72 from patients with benign biliary conditions. The concentrations of 6 compounds (acetaldehyde, acetone, benzene, carbon disulfide, pentane, and trimethylamine [TMA]) were increased in patients with pancreatic cancer compared with controls (P < .05). By using receiver-operating characteristic curve analysis, we developed a model for the diagnosis of pancreatic cancer based on the levels of TMA, acetone, isoprene, dimethyl sulfide, and acetaldehyde. The model [10.94 +/- 1.8229* log (acetaldehyde) +/- 0.7600* log (acetone) +/- 1.1746* log (dimethyl sulfide) +/- 1.0901* log (isoprene) +/- 2.1401 * log (trimethylamine) R 10] identified the patients with pancreatic cancer (area under the curve = 0.85), with 83.3% sensitivity and 81.9% specificity. Limitations: Sample size. Conclusions: The measurement of biliary fluid VOCs may help to distinguish malignant from benign biliary strictures. Further studies are warranted to validate these observations.