SENTINEL NODE BIOPSY PROJECT

Dr. Jim Dooner Sentinel Node Project: The purpose of the Sentinel Node Dissection project is to allow surgeons to gain proficiency in the identification of the first (sentinel) node draining the primary tumor of the breast. It is based on the logic that the sentinel node will be the most likely site of early metastasis. Histopathologic examination of this node using immunohistochemical stains may identify the metastasis and thereby allow selection of patients who should then go on to have a more complete axillary dissection. The absence of metastatic disease in the sentinel node may allow for the avoidance of an axillary dissection in some patients. The goal of the project is to develop a high level of accuracy in identification of the sentinel lymph node as well as a high degree of correlation between the histopathologic status of the sentinel node and the remainder of the dissected axillary nodes. Until such time as the technique has become a standard of care, it is still recommended that the axillary nodes be removed according to previously established guidelines. (Further elaboration of this issue has recently been published in the CMAJ: Clinical practice guidelines for the care and treatment of breast cancer: 13. Sentinel lymph node biopsy, Cantin J. et al, CMAJ July 24,2001, Vol. 165,2 pp166-173. www.cma.ca/cmaj Procedure: Patients will receive an injection of technetium labeled sulfur colloid at the time of fine wire localization for non-palpable tumors, or within twenty-four hours preoperatively for palpable tumors. In the operating room 5cc of Isosulfan blue will be injected around the tumor or peri-areolar and gently massaged for 5 minutes. A hand held gamma counter is used to detect the area of greatest concentration of radio-colloid in the axilla and if possible, an incision is made directly y over the suspected node. A trail of green lymphatics may be encountered that facilitate the location of the sentinel node. The suspected node is checked for its radioactivity, presence of dye and is excised. A count of the node ex-vivo is recorded and the node is sent to pathology. If additional nodes are identified, they are handled in the same way. The Axillary node dissection is completed in the usual fashion. The learning curve for the technique is variable but it is suggested between twenty to thirty cases allows for the development of proficiency in the identification of the sentinel node(s). It is expected to be several years before an analysis of outcomes will allow conclusions to be drawn regarding the influence of this technique on outcome. At present the standard of care is still the performance of an axillary node dissection. Fine wire localization of non-palpable breast tumour prior to injection of isosulfan blue, 5cc in the periareolar subdermal layer. Gamma probe used to localize suspected Sentinel node. Stained lymphatic demonstrated. Further dissection tracing the stained lymphatic vessel. Lymph node heavily stained with isosulfan blue identified and removed for examination.