Sentinel lymph node mapping in breast cancer.

Sentinel lymph node (SLN) biopsy is a rapidly emerging treatment option for the patient 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. With experience, using radioisotope, blue dye, or both, SLN are successfully localized in more than 90% of cases. The effects of isotope and blue dye may be additive. The SLN 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 one's early experience. Enhanced pathologic analysis, including serial sections and immunohistochemical staining, is an essential element of the procedure. In experienced hands, SLN biopsy has less morbidity and greater accuracy than conventional axillary dissection.