Enhanced touch preps improve the ease of interpretation of intraoperative breast cancer margins

Positive margins and the resulting multiple operations are a major problem for breast conservation therapy. Accurate assessment of intraoperative tumor margins can limit multiple re-excision procedures. Intraoperative touch preparations have been used in the past but can be difficult to interpret without an experienced cytopathologist. The objective of this study is to examine the reliability of enhanced intraoperative touch preps (EIOTP) compared with final pathologic margins. We prospectively performed EIOTP on 20 tumors in women undergoing breast conservation therapy. Six margins and the main tumor were touched onto poly-L-lysine coated slides. The slides were stained with anti MUC1 and anti-E-cadherin antibodies, and Hoechst nuclear stain. A parallel set of slides were stained with hematoxylin and eosin for comparison. The EIOTP results were compared with pathologic interpretation of paraffin embedded permanent sections. A total of 120 margins underwent EIOTP in 20 patients. We found a sensitivity equal to 80 per cent, specificity 100 per cent, positive predictive value 100 per cent, and negative predictive value 99 per cent. EIOTP in conjunction with MUC-1 and E-cadherin by immunofluorescence is a sensitive and highly specific mechanism to identify cancer cells at breast tissue margins. The immunofluorescence stains may help the pathologist to identify cancer cells in fresh breast tissue and limit breast re-excisions in the future.