[Intraoperative labeling of sentinel lymph nodes with a combination of vital dye and radionuclide tracer--results in sentinel lymph node-positive patients]

Abstract

Background: Sentinel lymph node biopsy enhances the accuracy of tumor staging in patients with malignant melanoma and can help select candidates for regional lymphadenectomy. There are two techniques for identifying the sentinel lymph node: intradermal injection of a radionuclide tracer or of a blue dye. We evaluated both methods to determine how they can be best utilized to locate a sentinel lymph node.

Patients and methods: In a retrospective study, 323 patients with melanoma (tumor thickness > or = 0.75 mm) who underwent sentinel lymph node biopsy after both radionuclide and blue dye injection were evaluated. The labeling of lymph nodes showing micrometastasis by histopathological examination was determined.

Results: 63 patients showed sentinel lymph nodes with micrometastasis. All of these nodes (100 %) were labeled with radionuclide tracer, but only 90 % with blue dye. In 5 patients, only radionuclide labeling identified the histopathologically-positive lymph node. In 36 patients, several sentinel lymph nodes were identified, with the histopathologically-positive nodes usually showing a higher radioactive signal intensity than the negative ones.

Conclusion: Since in some patients histopathologically-positive lymph nodes are only labeled by radionuclide tracer, radionuclide labeling is indispensable for locating sentinel lymph nodes. In contrast, labeling with blue dye represents a supplementary method, which can simplify the recognition of the sentinel lymph node during surgery.