A total of 393 nipple discharge or scrape smears from 360 women were e
xamined cytologically over a 12-year period. Twenty-nine breast cancer
s (8 per cent) have been histologically confirmed in this group, of wh
ich 16 had malignant smear cytology (sensitivity 55 per cent). Nine pa
tients with breast cancer and positive cytology had impalpable tumours
. Two of these cancers were not detected by any other investigation. T
hirteen patients with nipple discharge had false-negative cytology, bu
t there were no false-positive results (specificity 100 per cent). All
patients with expressible or spontaneous nipple discharges and those
with skin changes at the nipple should undergo examination of cytologi
cal smears.