ASCO convened an Expert Panel to conduct a systematic review of the literature available through February 2004 on the use of sentinel lymph node biopsy (SNB) in early-stage breast cancer. The Panel supports the use of SNB for staging disease in most women with clinically negative axillary lymph nodes. SNB is a reliable technique in trained hands and has an acceptable false-negative rate in the setting of both mastectomy and breast-conserving surgery.  The Panel recommends that suspicious palpable nodes should also be submitted as SLNs, and that in this context, the surgeon should have a low threshold for default to ALND.

Metastasis is found in non sentinel nodes in about 10% of patients with isolated tumor cells in the SLN and in 20% to 35% of patients with micrometastasis in the SLN. Until further studies addressing the clinical relevance of isolated tumor cells or micrometastases in the SLN are complete, the Panel recommends routine ALND for patients with micrometastases (> 0.2 mm but ≤ 2.0 mm) found on SNB, regardless of the method of detection.

Limitations in understanding the full role of this procedure in the management of women with early-stage breast cancer will not be addressed until the results of ongoing randomized trials are available.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2794562/