LYMPHOSCINTIGRAPHY, THE SENTINEL NODE CONCEPT, AND THE INTRAOPERATIVEGAMMA-PROBE IN MELANOMA, BREAST-CANCER, AND OTHER POTENTIAL CANCERS

There is a resurgence of interest in lymphoscintigraphy because of att ention to the sentinel node concept and the availability of the surgic al gamma probe that can be used in the operating room to localize radi olabeled sentinel nodes. Conventional surgical management of melanoma has been altered for intermediate thickness tumors such that lymph nod e dissection is performed for a lymph node bed only if the sentinel no de is tumor positive on histological exam after gamma probe-guided exc ision. This approach is cost effective, saving about 80% of these pati ents (sentinel node tumor negative) the cost and morbidity of unnecess ary ''elective lymph node dissection.'' In addition, a biopsy can be p erformed on all lymph node beds that receive lymphatic drainage from t he tumor site thereby improving staging and perhaps survival by provid ing the most appropriate therapy. Substantial work has been done to de velop optimum imaging techniques and the best radiopharmaceutical prep aration to achieve accurate, reproducible lymphatic drainage images. O ur methodology includes the following intradermal injections of a tech netium 99m sulfur colloid (modified preparation) are followed by dynam ic imaging (10 seconds per frame); static imaging up to 30 minutes and late imaging at 1 to 2 hours. Images show lymphatic channels that lea d to sentinel nodes in 1, 2, 3, or more anatomic locations. Surgical m anagement is altered to include sampling sentinel nodes of nodal beds, many of which would not have been sampled by previous conventional su rgical estimates of lymphatic drainage. While clinical success of lymp hoscintigraphy and intraoperative probe localization of the sentinel n ode in melanoma is evident, use of lymphoscintigraphy and the sentinel node concept in breast cancer is investigative, but promising. The ra diopharmaceutical is injected around the tumor in the breast followed by imaging to delineate lymphatic drainage to the sentinel node(s). Op timum methodologies for radiopharmaceutical, volume and/or activity of injectate, and imaging have yet to be determined. Breast lymphatic dr ainage can be to axilla, internal mammary, and/or supraclavicular node s in any combination. Copyright (C) 1997 by W.B. Saunders Company.