Lymphatic Mapping and Sentinel Lymph Node Biopsy for Breast Cancer: Developments and Resolving Controversies

It has now been over 10 years since lymphatic mapping and sentinel lymph node (SLN) biopsy was first used in patients with breast cancer. Since the procedure was introduced, over 1,500 studies on SLN biopsy in breast cancer have been published in the cited world medical literature. Over 11,000 women have been enrolled in National Cancer Institute–sponsored SLN biopsy trials for breast cancer, the final results of which will not be available until several years from now. In the meantime, both the National Comprehensive Cancer Network treatment guidelines in the United States and the Saint Gallen International Consensus Conference on the treatment of breast cancer have now indicated that SLN biopsy is an acceptable alternative to axillary lymph node dissection in patients with clinically nodenegative breast cancer, provided that the SLN team has documented experience with this technique. Simply stated, although long-term follow-up data are not yet available from randomized trials comparing SLN biopsy with axillary lymph node dissection, SLN biopsy has become an acceptable alternative to routine level I and II axillary lymph node dissection for women with clinically node-negative early-stage breast cancer in the United States and in several other developed countries. However, despite a clear picture of increasing integration of SLN biopsy into standard diagnostic and therapeutic strategies for breast cancer, there are several clinical scenarios in which the utility of this technique has been questioned. This article will focus on current and resolving controversies associated with breast cancer lymphatic mapping and SLN biopsy.