The risk of axillary relapse after sentinel lymph node biopsy for breast cancer is comparable with that of axillary lymph node dissection: a follow-up study of 4008 procedures

We sought to identify the rate of axillary recurrence after sentinel lymph node (SLN) biopsy for breast cancer.SLN biopsy is a new standard of care for axillary lymph node staging in breast cancer. Nevertheless, most validated series of SLN biopsy confirm that the SLN is falsely negative in 5-10% of node-positive cases, and few studies report the rate of axillary local recurrence (LR) for that subset of patients staged by SLN biopsy alone.Through December of 2002, 4008 consecutive SLN biopsy procedures were performed at Memorial Sloan-Kettering Cancer Center for unilateral invasive breast cancer. Patients were categorized in 4 groups: SLN-negative with axillary lymph node dissection (ALND; n = 326), SLN-negative without ALND (n = 2340), SLN-positive with ALND (n = 1132), and SLN-positive without ALND (n = 210). Clinical and pathologic characteristics and follow-up data for each of the 4 cohorts were evaluated with emphasis on patterns of axillary LR.With a median follow-up of 31 months (range, 1-75), axillary LR occurred in 10/4008 (0.25%) patients overall. In 3 cases (0.07%) the axillary LR was the first site of treatment failure, in 4 (0.1%) it was coincident with breast LR, and in 3 (0.07%) it was coincident with distant metastases. Axillary LR was more frequent among the unconventionally treated SLN-positive/no ALND patients than in the other 3 conventionally treated cohorts (1.4% versus 0.18%, P = 0.013).Axillary LR after SLN biopsy, with or without ALND, is a rare event, and this low relapse rate supports wider use of SLN biopsy for breast cancer staging. There is a low-risk subset of SLN-positive patients in whom completion ALND may not be required.