Systematic review and meta-analysis of the diagnostic accuracy of ductoscopy in patients with pathological nipple discharge

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 DS_any, all visualized ductoscopic abnormalities were classified as positive, whereas for DS_susp, only suspicious findings were considered positive. After checking heterogeneity, pooled sensitivity and specificity of DS_any and DS_susp were 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 DS_any were 94 (95 per cent c.i. 88 to 97) per cent and 47 (44 to 49) per cent respectively. Pooled sensitivity and specificity of DS_susp were 50 (36 to 64) and 83 (81 to 86) per cent respectively. Heterogeneity between studies was moderate to large for sensitivity (DS_any: I² = 17·5 per cent; DS_susp: I² = 37·9 per cent) and very large for specificity (DS_any: I² = 96·8 per cent; DS_susp: I² = 92·6 per cent). Conclusion 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.