title: How many cytological examinations should be performed for the diagnosis of malignant biliary stricture via an endoscopic nasobiliary drainage tube?
abstract: OBJECTIVE
  The sensitivity of bile cytology is recognized as being low. Repeating cytological sampling is likely to improve the sensitivity. The aim of this study is to determine the optimal number of repeated cytological sampling of bile obtained via an endoscopic nasobiliary drainage (ENBD) tube for the diagnosis of malignant biliary stricture.
  
  
  METHODS
  Ninety-eight patients with malignant biliary stricture who underwent ENBD were enrolled. Diagnoses included bile duct carcinoma (n = 53), pancreatic carcinoma (n = 28), carcinoma of the major papilla (n = 8), gallbladder carcinoma (n = 6), and hepatocellular carcinoma (n = 3). Bile was aspirated via an ENBD tube once a day and immediately evaluated cytologically.
  
  
  RESULTS
  The median number of cytological samplings via an ENBD tube was 2.8 times (range, 1-10). In 40 of 98 patients with malignant biliary stricture, cytology was positive at the first cytological sampling (sensitivity 40.8%). Cytology was cumulatively positive in 71 of 98 patients (sensitivity 72.4%) from which repeated samples were taken. In 71 patients with positive cytology, correlation of the positive rate and the number of cytological samplings performed was investigated. In 68 of 71 (95.8%) patients with positive cytology, positive results were obtained by or at the sixth examination.
  
  
  CONCLUSIONS
  Bile cytology via an ENBD tube is an easy method, and has been shown to have relatively high sensitivity. The optimal number of repeated cytological samplings using bile obtained via an ENBD tube for the diagnosis of malignant biliary stricture was concluded to be six.
authors.affiliation: Department of Gastroenterology and Neurology, Kagawa University School of Medicine, Kagawa, Japan. naohito@kms.ac.jp
authors.forename: Naohito
authors.initials: N
authors.lastname: Uchida
authors.forename: Hideki
authors.initials: H
authors.lastname: Kamada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ono
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Aritomo
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Masaki
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakatsu
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kuriyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001646:Bile / Q000166:cytology*; D001650:Bile Duct Neoplasms / Q000150:complications / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000150:complications / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000150:complications / Q000473:pathology; D002779:Cholestasis / Q000209:etiology* / Q000473:pathology; D004067:Digestive System Neoplasms / Q000150:complications / Q000473:pathology*; D020776:Endoscopes, Gastrointestinal; D016145:Endoscopy, Digestive System / Q000295:instrumentation*; D005260:Female; D005706:Gallbladder Neoplasms / Q000150:complications / Q000473:pathology; D006801:Humans; D007441:Intubation, Gastrointestinal / Q000295:instrumentation*; D008113:Liver Neoplasms / Q000150:complications / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000150:complications / Q000473:pathology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013396:Suction / Q000295:instrumentation