White bile in patients with malignant biliary obstruction is an independent factor of poor survival.

Background and study aims White bile is defined as a colorless fluid occasionally found in the biliary tract of patients with bile duct obstruction. Its significance is not clearly established. Our objective was to analyze the prognostic value of white bile in a series of patients with biliary obstruction due to biliary or pancreatic cancer. Patients and methods The study was conducted on a series of consecutive patients with malignant obstructive jaundice. They all underwent endoscopic retrograde cholangiopancreatography with collection of bile and biliary stent insertion. White bile was defined as bile duct fluid with bilirubin level < 20 µmol/L. Univariate and multivariate analyses were performed to identify variables associated with overall survival (OS). Results Seventy-three patients were included (32 pancreatic cancers, 41 bile duct cancers). Thirty-nine (53.4 %) had white bile. The mean bile duct bilirubin level in this group was 4.2 ±â€Š5.9 µmol/L vs 991 ±â€Š1039 µmol/L in patients with colored bile (P < 0.0001). In the group of 54 patients not eligible for surgery, the multivariate analysis demonstrated an association between the presence of white bile and reduced OS (HR 2.3, 95 %CI 1.1-4.7; P = 0.02). Other factors independently associated with OS were metastatic extension (HR 2.8, 95 %CI 1.4-5.7) and serum total bilirubin (HR 1.003, 95 %CI 1.001-1.006). There was a significant inverse correlation between serum and bile duct bilirubin levels (r = -0.43, P = 0.0001). Conclusion White bile in patients with inoperable malignant biliary obstruction is an independent factor of poor survival.

Bile analysis using high-throughput FTIR spectroscopy for the diagnosis of malignant biliary strictures: a pilot study in 57 patients.

This study aimed at determining whether FTIR spectroscopy is able to distinguish bile samples from patients with and without malignant biliary strictures. Bile samples were collected in 19 patients with malignant biliary strictures and 38 with benign biliary diseases during endoscopic procedures. FTIR spectra were acquired on dried drops of whole bile, aqueous and organic phases obtained after lipid extraction. Data were analyzed by principal component analysis and by the support vector machine classification using a leave-n-out cross validation procedure. This was applied to the whole set of spectra and the mean and median spectra of each patient. By leaving one patient out, the classifier allowed discriminating patients with and without malignant biliary strictures with a sensitivity between 82% and 95% and a specificity between 85% and 100%. Using a randomized leave-n -out cross-validation with n = 2, 5 and 10 patients, the sensitivity decreased slightly by about 5 to 10% while the specificity remained stable, suggesting the robustness of the classifier. FTIR spectroscopy combined with chemometrics therefore shows potential to differentiate bile from patients with and without malignant biliary strictures. Although promising, the results of this pilot study cannot be generalized and needs to be confirmed in a larger population.