Use of touch preps for intraoperative diagnosis of sentinel lymph node metastases in breast cancer.

Background: Intraoperative touch prep (TP) is highly accurate for determining positive breast cancer margins and thereby reducing the need for second surgeries. It also may be useful in determining the status of the sentinel lymph node (SLN) during the initial surgical resection. The objective of this study was to test the ability of intraoperative TP to predict metastatic disease and, thus, the necessity for axillary lymph node dissection (ALND) at the time of SLN biopsy.

Methods: Fifty-five patients with invasive breast cancer were entered in the SLN biopsy protocol. The SLN was identified by gamma probe, dissected, and sent to pathology for TP and permanent sections. Level I and II ALND was then performed. Any radiolabeled LN in the lymphadenectomy specimen also was sent for TP and permanent sections.

Results: A total of 124 radiolabeled lymph nodes (LNs) were submitted for TP; of these, 93 (75%) were SLNs. Pathologic diagnosis by TP was correct compared with permanent sections for 99.2% of the nodes. There were no false positives. There was one (0.8%) false negative. The positive predictive value was 100% and the negative predictive value was 99%. Sensitivity was 95.7% and specificity was 100%.

Conclusions: TP is a simple, quick, and accurate method for detecting metastatic disease in the SLN and, when used intraoperatively, enables the surgeon to determine whether or not an ALND is necessary at the time of the initial surgery.