The investigation and management of unilateral nipple discharge.

INTRODUCTION: Between 16,000 and 48,000 women are estimated to present to UK breast clinics with nipple discharge each year. The incidence of malignancy in these women is 2.7-24.2%. Currently, there is no consensus on the best way to investigate and manage these women. The aim of this study was to assess the rate of malignancy in women presenting with unilateral nipple discharge, and to evaluate the role of examination, imaging and cytology in reliably predicting outcome. METHODS: Breast units were asked to prospectively collect data on all new patients with unilateral nipple discharge. Data collected included discharge colour, whether it was uniductal or multiductal, examination and imaging findings, cytology results and outcome. RESULTS: Complete datasets were submitted by 5 units on 228 patients. The incidence of malignancy was 4.4%. Clinical examination was valuable in detecting malignancy and multiductal discharge was not related to malignancy. The positive predictive value for detecting malignancy for an abnormality found on mammography was 53.5% and for ultrasonography, it was 65.2%. The role of cytology in detecting malignancy was inconclusive with positive predictive values of the presence of red blood cells and epithelial cells at 6.1% and 10.7% respectively. CONCLUSIONS: A large number of women are investigated for nipple discharge (with huge resource implications) but there is little reliable evidence on the best way to investigate and manage these patients. A larger study is needed to evaluate the role of investigations in nipple discharge to produce guidelines on optimal management.