title: Systematic review and meta-analysis of the diagnostic accuracy of ductoscopy in patients with pathological nipple discharge.
abstract: BACKGROUND
  Invasive surgery remains the standard for diagnosis of pathological nipple discharge (PND). Only a minority of patients with nipple discharge and an unsuspicious finding on conventional breast imaging have cancer. Ductoscopy is a minimally invasive alternative for evaluation of PND. This systematic review and meta-analysis was designed to evaluate the diagnostic accuracy of ductoscopy in patients with PND.
  
  
  METHODS
  A systematic search of electronic databases for studies addressing ductoscopy in patients with PND was conducted. Two classification systems were assessed. For DSany, all visualized ductoscopic abnormalities were classified as positive, whereas for DSsusp, only suspicious findings were considered positive. After checking heterogeneity, pooled sensitivity and specificity of DSanyand DSsuspwere calculated.
  
  
  RESULTS
  The search yielded 4642 original citations, of which 20 studies were included in the review. Malignancy rates varied from 0 to 27 per cent. Twelve studies, including 1994 patients, were eligible for meta-analysis. Pooled sensitivity and specificity of DSanywere 94 (95 per cent c.i. 88 to 97) per cent and 47 (44 to 49) per cent respectively. Pooled sensitivity and specificity of DSsuspwere 50 (36 to 64) and 83 (81 to 86) per cent respectively. Heterogeneity between studies was moderate to large for sensitivity (DSany: I2= 17·5 per cent; DSsusp: I2= 37·9 per cent) and very large for specificity (DSany: I2= 96·8 per cent; DSsusp: I2= 92·6 per cent).
  
  
  CONCLUSIONS
  Ductoscopy detects about 94 per cent of all underlying malignancies in patients with PND, but does not permit reliable discrimination between malignant and benign findings.
authors.affiliation: Departments of Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Waaijer
authors.affiliation: Departments of Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Simons
authors.affiliation: Departments of Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: I H M
authors.initials: IH
authors.lastname: Borel Rinkes
authors.affiliation: Departments of Pathology, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: P J
authors.initials: PJ
authors.lastname: van Diest
authors.affiliation: Imaging Division, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: H M
authors.initials: HM
authors.lastname: Verkooijen
authors.affiliation: Departments of Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Witkamp
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D004724:Endoscopy / Q000379:methods*; D005122:Exudates and Transudates; D005260:Female; D006801:Humans; D000071936:Nipple Discharge; D009558:Nipples / Q000473:pathology*; D012680:Sensitivity and Specificity