The clinical impact and outcomes of immunohistochemistry-only metastasis in breast cancer.

Overview

BACKGROUND: Modern surgical and pathological techniques can detect small-volume axillary metastases in breast cancer with unknown clinical significance. METHODS: A retrospective database review from 1996 through 2004 identified all patients with immunohistochemical (IHC)-only sentinel node (IHC-SN) metastases and compared them with negative controls (Neg-SN). RESULTS: When comparing the 232 IHC-SN patients with the 252 Neg-SN controls, the IHC-SN patients had larger tumors, more lobular histology, a higher grade, and more HER2/neu positivity. They also received more systemic therapy. With a median follow-up of 5 years, there were no differences in recurrence-free survival or overall survival. In 123 IHC-SN patients treated with axillary dissection (axillary lymph node dissection), 16% had positive non-SLNs. Patients with positive non-SLNs tended to have worse outcomes. CONCLUSIONS: IHC-only sentinel lymph node (SLN) metastases were associated with worse prognostic features and higher rates of systemic therapy. However, no outcomes differences were noted.