Sentinel lymph node mapping in breast cancer.

Sentinel lymph node (SLN) biopsy is a rapidly emerging treatment option for patients with early-stage invasive breast cancer and a clinically negative axilla. In the era of mammographic detection, SLN biopsy has the potential to eliminate axillary dissection for the enlarging cohort of breast cancer patients who are node-negative. Using radioisotope, blue dye, or both methods, experienced surgeons can successfully localize SLNs in more than 90% of cases. The effects of isotope and blue dye may be additive. Sentinel lymph node biopsy reliably predicts axillary node status in 98% of all patients and 95% of those who are node-positive. The operation is best learned under a formalized protocol in which a backup axillary dissection is performed to validate the technique during the surgeon's early experience. Enhanced pathologic analysis, including serial sections and immunohistochemical (IHC) staining, is an essential element of the procedure. In experienced hands, SLN biopsy has less morbidity and greater accuracy than conventional axillary dissection.