Expanding the Indications for Sentinel Lymph Node Surgery in Breast Cancer

Abstract

Nodal evaluation in breast cancer patients is important for staging and continues to be the strongest indicator of breast cancer outcome. This information is used to make treatment decisions, including chemotherapy and radiation therapy, in individual patients. The removal of lymph nodes that contain metastatic disease also plays a role in local–regional control. Historically, this has been performed with an axillary lymph node dissection (ALND). Over the last 15 years, sentinel lymph node (SLN) surgery has been established as a replacement for ALND in patients with breast cancer and its use and indications are expanding. SLN surgery was described initially in the management of patients with clinically node-negative melanoma and was translated into the breast cancer population in the early 1990s by Krag [1] and Guiliano [2]. The benefits of SLN surgery are that it can avoid the need for ALND in node-negative patients and result in a decreased complication rate compared with ALND, particularly in terms of the development of lymphedema, impaired shoulder mobility and paresthesias [3,4]. Initially, its use was limited to patients with T1 or T2 tumors and a clinically negative axilla. Relative contraindications for the use of this technique have included large primary tumor size, inflammatory breast cancer, multifocal or multicentric disease, use of preoperative chemotherapy, prior breast or axillary surgery of any kind, previous breast augmentation or breast reduction surgery, and pregnancy. As our experience with SLN surgery has evolved, the identification rate of SLNs at surgery has improved and false-negative rates have decreased. A review of the published literature demonstrates that the identification rate of the SLN ranges from 90–95% and the false-negative rate of SLN surgery varies between 5–10%. The procedure is either performed with the use of radioisotope, blue dye or both. The most commonly used blue dye is isosulfan blue dye (LymphazurinTM), although methylene blue is used in some centers. The consensus statement by the American Society of Breast Surgeons advocates that the radioactive tracer and the blue dye are both used to increase the identification rate and decrease the false-negative rate of SLN surgery. A SLN is defined as a node which is radioactive, blue or palpably abnormal. The indications for SLN surgery are expanding as experience with SLN surgery grows and evidence regarding the feasibility and accuracy of SLN surgery in various different patient subgroups becomes available.