SAN FRANCISCOIn patients with breast cancer, sentinel lymph node
mapping enables a detailed pathologic examination of nodal tissue by multilevel
microsections with standard hematoxylin and eosin staining (H&E) and highly
sensitive immunohistochemical (IHC) staining. However, the significance of IHC
metastases remains unknown.
At the 37th Annual Meeting of the American Society of Clinical Oncology
(ASCO abstract 91), Nora M. Hansen, MD, of the John Wayne Cancer Center, Santa
Monica, California, presented results of a prospective study showing that a
positive finding by IHC staining does not predict poorer overall survival.
Between 1992 and 1999, 683 patients in the trial underwent lymphatic mapping
using blue dye with or without radioactive colloid. The sentinel node was
examined by both H&E and IHC staining. A total of 603 patients were
available for evaluation.
Patients were stratified into four groups based on their sentinel node
The negative sentinel node group had 419 patients (group 1). Positive
sentinel nodes were found in 264 patients. Of these patients, 56 patients had
IHC-positive/H&E negative metastases (group 2). Sentinel node H&E
micrometastases (2 mm or less) were found in 76 patients (group 3) and sentinel
node H&E macrometastases (greater than 2 mm) in 132 patients (group 4).
Five-year disease-free survival and overall survival were estimated for each
group. At a median follow-up of 44 months, the size of sentinel
node metastases was a significant predictor of disease-free survival (P =
.0001) and overall survival (P = .0036). There was no significant difference in
disease-free or overall survival between sentinel-node-negative patients an sentinel-node IHC-positive patients.