How Do Pathologists in Academic Institutions Across the United States and Canada Evaluate Sentinel Lymph Nodes in Breast Cancer? A Practice Survey.

ABSTRACT

OBJECTIVES: There are little data on how changes in the clinical management of axillary lymph nodes in breast cancer have influenced pathologist evaluation of sentinel lymph nodes. METHODS: A 14-question survey was sent to Canadian and US breast pathologists at academic institutions (AIs). RESULTS: Pathologists from 23 AIs responded. Intraoperative evaluation (IOE) is performed for selected cases in 9 AIs, for almost all in 10, and not performed in 4. Thirteen use frozen sections (FSs) alone. During IOE, perinodal fat is completely trimmed in 8, not trimmed in 9, and variable in 2. For FS, in 12 the entire node is submitted at 2-mm intervals. Preferred plane of sectioning is parallel to the long axis in 8 and perpendicular in 12. In 11, a single H&E slide is obtained, whereas 12 opt for multiple levels. In 11, cytokeratin is obtained if necessary, and immunostains are routine in 10. Thirteen consider tumor cells in pericapsular lymphatics as lymphovascular invasion (LVI), and 10 consider it isolated tumor cells (ITCs). CONCLUSIONS: There is dichotomy in practice with near-equal support for routine vs case-by-case multilevel/immunostain evaluation, perpendicular vs parallel sectioning, complete vs incomplete fat removal, and tumor in pericapsular lymphatics as LVI vs ITCs.