Intraoperative imprint cytology of sentinel nodes in breast cancer.

Background and Objectives: Sentinel node (SN) biopsy is a new standard of care for axillary node staging in patients with early-stage, clinically node-negative breast cancer. A second operation can be avoided when the results are available intraoperatively. However, there is no standard intraoperative method for SN assessment. The aim of this study was to evaluate intraoperative imprint cytology (IC) for the detection of SN involvement in patients with early-stage breast cancer.
Methods: One hundred eighty-five consecutive patients with a breast tumor underwent SN biopsy with intraoperative IC. The SN was bisected and a touch preparation was made with a glass slide, on both sides of the cut. Permanent sections were evaluated with H&E and immunohistochemical staining. The IC results were compared with the final histologic results.
Results: The sensitivity, specificity, accuracy, and positive and negative predictive values of IC were 33.3, 78.4, 78.9, 90, and 77.5%, respectively. IC was more sensitive for macrometastases than for micrometastases. In the 118 patients studied after the learning phase, 9 patients with a positive SN by IC avoided a second operation.
Conclusions: Intraoperative IC of SNs appears to be reasonably reliable in patients with breast cancer, permitting axillary dissection during the same surgical procedure when positive. In contrast, sensitivity for detection of micrometastases is low.
(Copyright 2004 Wiley-Liss, Inc.)