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

Navaneethan U, Parsi MA, Gutierrez NG, Bhatt A, Venkatesh PG, Lourdusamy D, Grove D, Hammel JP, Jang S, Sanaka MR, Stevens T, Vargo JJ,Dweik RA. Volatile organic compounds in bile can diagnose malignant biliary strictures in the setting of pancreatic cancer: a preliminary observation. Gastrointest Endosc. 2014 Dec;80(6):1038-45. doi: 10.1016/j.gie.2014.04.016. PMID: 24929484

Abstract
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 pancreaticcancer.
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 benignbiliary 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) ≥ 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. (Clinical Trial Registration Number NCT01565460.).