Sentinel lymph node biopsy has rapidly evolved into the standard of care for node-negative melanoma. It has been used at the Roswell Park Cancer Institute (RPCI) since 1993, and through periodic reviews of results, several modifications have been made to improve outcomes and contribute to the evolution of sentinel lymph node biopsy. Michael S. Sabel, MD, and William G. Kraybill, MD, of RPCI’s department of surgery, and colleagues, reported on the latest such review in a recent issue of the journal, Surgery (128:556-563, 2000).
"Presently, there is great variation from hospital to hospital in the technique of intraoperative sentinel lymph node mapping," said Dr. Sabel. "Several aspects of the technique have changed and evolved since it was described initially in 1992. If sentinel lymph node biopsy is to be the standard of care, these improvements in technique must be disseminated so that 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 clinically node-negative primary cutaneous melanoma, who had undergone sentinel lymph node biopsy between January 1993 and December 1998 at RPCI, were reviewed and assessed for the technique used to identify the sentinel lymph node, pathologic evaluation, and use of the intraoperative frozen section. Results indicated that:
the accuracy of sentinel lymph node identification improved from 91% to 100% with the combination of isosulfan blue dye and radiolabeled colloid over isosulfan blue dye alone;
routine rather than selective lymphoscintigraphy identified seven in-transit sentinel lymph nodes and increased detection of dual basin drainage from 15% to 27%; and
identification of micrometastases in the sentinel lymph node increased from 14% to 24% after discontinuing the frozen section analysis of the sentinel lymph node in favor of processing tissue for permanent paraffin(Drug information on paraffin) sectioning with multiple hematoxylin and eosin levels and S-100 and HMB-45 immunochemistry evaluations.
"Through this careful review and strong collaboration with colleagues in nuclear medicine and pathology, several areas have been identified where sentinel lymph node biopsy may be improved," said Dr. Kraybill. "We believe this approach is necessary if the benefits of the technique for malignant melanoma are to be realized."