ABSTRACT
Introduction ......................................................................................................................... 106 Pathology P rotocol............................................................................................................. 107 Pa thologic Findings............................................................................................................ 108 Results................................................................................................................................... I l l C onclusion ........................................................................................................................... 113
INTRODUCTION
Lymphatic mapping utilizing technetium labeled sulfur colloid and isosulfan blue dye injections has successfully identified the sentinel lymph nodes (SLNs) and allowed accurate staging.1·2 This minimally invasive technique may lead to more conservative lymph node dissection for stages I and II breast cancer patients with decreased morbidity and cost savings for the health care system. For most cancers, the nodal status is the single most important prognostic indicator and determines the need in many cases for adjuvant chemotherapy.3 Micrometastases in the axillary lymph nodes has been reported to be associated with poorer sur vival.4 Currently, there is a failure rate of 15% to 20% at five years in node-nega tive patients which may be attributed to the low detection rate o f micrometastases using the routine hematoxylin and eosin (H&E) stain.5 With the advent of lym phatic mapping, these SLNs may be carefully and thoroughly evaluated for suc cessful identification o f micrometastases as SLN involvement determines whether the surgeon will perform a complete lymph node dissection (CLND). Generally, frozen section is not recommended for lymph node tissue as it causes extensive freezing artifacts and may obscure the histology of the tumor or lose the micro scopic metastatic tumor cells in the cryostat. In addition, traditional staining meth ods with H&E alone on sectioned lymph nodes may not detect the micrometastatic tumor cells in a background of millions o f lymphocytes. We have developed a protocol utilizing an intraoperative imprint cytology (IIC) of the SLNs to con firm the metastatic tumor in grossly positive and suspicious nodes and to identify micrometastases in grossly negative nodes. IIC has therefore become a crucial part o f our intraoperative surgical management, enabling the immediate decision for CLND. IIC is followed by a standard histopathology protocol in concert with an cillary im m unohistochem ical stain for low m olecular weight cytokeratin (CAM 5.2) on grossly negative SLNs. Radioguided Surgery, edited by Eric D. Whitman and Douglas Reintgen. © 1999 Landes Bioscience
PATHOLOGY PROTOCOL
The radiolabeled SLNs are submitted to the pathology processing room iden tified as SLN 1, SLN 2, SLN 3, etc. SLNs are bisected intraoperatively and exam ined for any gross evidence o f metastatic disease. About one-quarter o f the SLN is then snap frozen in the operating room for RT-PCR analysis for other protocols. At our institution, all physicians including surgeons, radiologists, pathologists, nuclear medicine staff and intraoperative personnel routinely wear radiation monitoring badges.
