The accuracy of nipple discharge cytology in detecting breast cancer.

Abstract

This study aimed to disclose the importance of nipple discharge (ND) and the accuracy of its economic and fast cytological interpretation. All ND cytology cases for Saudi patients done between 2004 and 2013 were retrieved from the Pathology e-system. Only cases that have subsequent tissue diagnoses were included in this study (n=228). Age and bloody nature of the ND were both tested for association with a higher chance of carcinoma. Diagnostic accuracy of ND cytology was calculated twice, including and excluding the "atypical" cases. Specificity and positive predictive value were 100% for ND cytology in both cases. Sensitivity (34.6%; 52.9%), negative predictive value (93.15 %; 96.1%), false-negative rate (65.4%; 47.1%), accuracy rate (93.4%; 96.2%), when atypical cases were included and excluded; respectively. Only 10.5% of the patients complaining from nipple discharge had breast cancer. For those who had cancer, nipple discharge cytology was positive and showed the cancer cells in only 37.5%, while the rest were false negative. Bloody ND disclosed a significant association with malignancy (p<0.001), but the association was statistically not significant for old age (p=0.062). The prospect of having breast cancer with the presentation of ND is low, and it can be missed by studying the ND cytology alone in a high proportion of cases. Excluding the atypical category did not make a significant improvement in the test's accuracy.