Clinical Practice Guidelines for the Use of Axillary Sentinel Lymph Node Biopsy in Carcinoma of the Breast: Current Update

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Abstract
Axillary sentinel lymph node biopsy (SLNB) has been adopted as a suitable alternative to traditional level I and II axillary dissection in the management of clinically node‐negative (N0) breast cancers. There are two current techniques used to identify the sentinel node(s): radiopharmaceutical, technetium sulfur colloid, and isosulfan blue dye (used in the United States) and technetium‐labeled albumin and patent blue dye (used in Europe). (The labeled albumin is not U.S. Food and Drug Administration [FDA] approved in the United States.) SLNB to replace axillary dissection should only be performed by surgeons and patient management teams with appropriate training and experience. Although both radiocolloid and blue dye are used together by most surgeons, and training should be in both techniques, some experienced surgeons use one or the other almost exclusively. In addition, surgical pathologists must recognize the need to examine these small specimens with great care, using a generally adopted protocol. Imprint cytology or frozen sections may be used, followed by additional sections for light microscopy. Immunochemical staining with cytokeratin or other techniques to identify “submicroscopic” metastasis is often used, but the results should not be used to influence clinical decisions with respect to adjuvant therapy. “Failed” SLNB implies the surgeon's failure to identify the sentinel nodes, in which case a complete dissection is performed. A “false‐negative” SLNB implies the finding of metastasis in the excised sentinel nodes by light microscopy after a negative frozen section examination. Whether a false‐negative SLNB mandates completion axillary dissection is controversial, with clinical trials currently under way to answer this question. Although SLNB was initiated to accompany breast‐conserving treatment, it is equally useful in patients undergoing mastectomy. It is more difficult to perform with mastectomy. When using blue dye only, SLNB may require a separate incision because of time constraints between injection and identification of the blue‐stained nodes; radiocolloid usually does not. Completion axillary dissection after false‐negative SLNB is more difficult after mastectomy. SLNB is a useful procedure that may save 70% of women with clinically negative (N0) axillae and all of those with pathologically negative axillae from the morbidity of complete axillary dissection. Ideally the sentinel nodes should be able to identified in more than 95% of patients, with a false‐negative rate of less than 5%. Until these rates can be achieved consistently, however, surgeons should not abandon traditional axillary dissection.