Usefulness of intraoperative touch smear cytology in breast-conserving surgery.

In breast-conserving surgery, positive margins are closely related to intramammary recurrence, but methods of assessing resection stumps during breast-conserving surgery have not been standardized. The present study investigated the usefulness of intraoperative touch smear cytology in our department. From 2005 to 2008, a total of 420 patients underwent breast cancer surgery. Subjects comprised 160 patients who underwent breast-conserving surgery and touch smear cytology. Results of the touch smear cytology were compared to those of the histological tissue analysis. Touch smear cytology displayed 70% sensitivity (14/20), 97.1% specificity (136/140) and a diagnostic accuracy of 93.8% (150/160). Six false-negative cases and 4 false-positive cases were identified. Of the 6 false-negatives, cancer cells were noted in the ductal component in 5 cases, and the degree of cancer cell atypia in the stump was low. Residual cancer cells were noted in the stump in 18 cases, and additional resection was performed in 16 cases. Cancer cells were identified histologically in the additionally resected tissue in 8 of these 16 cases (50%). The direction of positive cytology was towards the nipple in 16 cases, lateral tissue in 5 cases and contralateral nipple in 2 cases. A greater cancer cell volume, as assessed by touch smear cytology, tended to be associated with higher frequency of positive margins, as assessed by histological tissue analysis. Touch smear cytology is easy to perform, offering a very useful technique yielding comparable results to histological tissue analysis.