Nipple discharge and the efficacy of duct cytology in evaluating breast cancer risk

Background: Nipple discharge accounts for up to 5% of referrals to breast surgical services. With the vast majority of breast carcinomas originating in the ductal system, symptomatic dysfunction of this system often raises disproportionate clinical concern. The aim of this study is firstly, to evaluate the clinical importance of nipple discharge as an indicator of underlying malignancy and secondly, to assess the diagnostic application of duct cytology in patients presenting with nipple discharge.

Study design: We performed a retrospective analysis of all patients presenting with nipple discharge as their primary symptom to the symptomatic breast unit at a tertiary referral center over a 30-month period (n = 313). The Hospital Inpatient Enquiry (HIPE) System and BreastHealth database were used to identify our study cohort. Parameters evaluated included patient demographics, clinical presentation, clinical evaluation, radiological assessment and histological/cytological analysis.

Results: Three-hundred and thirteen patients presented with nipple discharge as their primary complaint. Invasive breast carcinoma was diagnosed by Triple Assessment in 5% of patients. 24% of patients presenting with nipple discharge underwent nipple aspiration and cytological analysis. Duct cytology was diagnostic of the underlying breast carcinoma in 50% of triple assessment diagnosed carcinoma. Four risk factors were identified as having a significant association with breast carcinoma, these included (a) age >50 years (p < 0.0001), (b) bloody nipple discharge (p < 0.008), (c) presence of a breast lump (p < 0.0001) and (d) single duct discharge (p < 0.006).

Conclusions: Nipple discharge is a poor indicator of an underlying malignancy. Use of nipple aspiration and duct cytology for the assessment of nipple discharge is of limited diagnostic benefit. However, by utilizing the systematic, gold standard approach of Triple Assessment (clinical, radiological and cytological evaluation), the risk of underlying carcinoma can be accurately defined.