Study Contributes to Evolution of Sentinel Lymph Node Biopsy for Melanoma

Sentinel lymph node biopsy has rapidly evolved intothe standard of care for node-negative melanoma. Ithas been used at the Roswell Park Cancer Institute (RPCI) since 1993, andthrough periodic reviews of results, several modifications have been made toimprove outcomes and contribute to the evolution of sentinel lymph node biopsy.Michael S. Sabel, MD, and William G. Kraybill, MD, of RPCI’s department ofsurgery, and colleagues, reported on the latest such review in a recent issue ofthe journal, Surgery (128:556-563, 2000).

"Presently, there is great variation from hospital tohospital in the technique of intraoperative sentinel lymph node mapping,"said Dr. Sabel. "Several aspects of the technique have changed and evolvedsince it was described initially in 1992. If sentinel lymph node biopsy is to bethe standard of care, these improvements in technique must be disseminated sothat it can be performed in a standardized manner," said Dr. Kraybill.

Nuclear Medicine and Pathology Improve Results

In the review, the charts of 182 patients with clinicallynode-negative primary cutaneous melanoma, who had undergone sentinel lymph nodebiopsy between January 1993 and December 1998 at RPCI, were reviewed andassessed for the technique used to identify the sentinel lymph node, pathologicevaluation, and use of the intraoperative frozen section. Results indicatedthat:

the accuracy of sentinel lymph node identification improvedfrom 91% to 100% with the combination of isosulfan blue dye and radiolabeledcolloid over isosulfan blue dye alone;

routine rather than selective lymphoscintigraphy identifiedseven in-transit sentinel lymph nodes and increased detection of dual basindrainage from 15% to 27%; and

identification of micrometastases in the sentinel lymph nodeincreased from 14% to 24% after discontinuing the frozen section analysis of thesentinel lymph node in favor of processing tissue for permanent paraffinsectioning with multiple hematoxylin and eosin levels and S-100 and HMB-45immunochemistry evaluations.

"Through this careful review and strong collaboration withcolleagues in nuclear medicine and pathology, several areas have been identifiedwhere sentinel lymph node biopsy may be improved," said Dr. Kraybill."We believe this approach is necessary if the benefits of the technique formalignant melanoma are to be realized."