The use of cytokeratin staining in sentinel lymph node biopsy for breast cancer.
BACKGROUND
Controversy exists regarding the routine use of cytokeratin immunohistochemistry (IHC) in the histopathologic examination of breast cancer sentinel lymph nodes (SLN) because the clinical significance of micrometastases detected by IHC is unclear. This analysis was performed to determine the frequency of IHC-detected micrometastases.


METHODS
All patients underwent SLN biopsy, followed by completion axillary dissection. This analysis included patients who had SLN evaluated by IHC. SLN were examined by hematoxylin and eosin (H&E) stain at 2-mm intervals, with IHC in 2 sections. The axillary dissection specimen was evaluated by routine H&E staining.


RESULTS
IHC was performed in SLNs from 973 patients. Of the 869 patients with negative nodes by H&E, 58 (6.7%) were "upstaged" by IHC. In 6 of 58 patients (10.3%) who had IHC-only positive SLN, nodal metastases were found in the axillary dissection specimen.


CONCLUSIONS
IHC resulted in upstaging of 6.7% of patients who had negative SLN on H&E staining. These patients had a 10.3% risk of residual axillary nodal metastases. However, the clinical significance of IHC-only positive SLN requires further study.
Wong
S L
SL
Department of Surgery, University of Louisville, J. Graham Brown Cancer Center, 529 S. Jackson St., No. 318, Louisville, KY 40202, USA.
Chao
C
C
Edwards
M J
MJ
Simpson
D
D
McMasters
K M
KM
D001365:Axilla; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008875:Middle Aged; D021701:Sentinel Lymph Node Biopsy
D007633:Keratins