A prospective study of intraoperative lymphatic mapping for head and neck cutaneous melanoma

Background: Intraoperative lymphatic mapping and sentinel lymph node biopsy have been used successfully to stage regional lymphatics for trunk and extremity melanomas. However, the accuracy and applicability of these techniques in the head and neck have not been determined conclusively. Objective: To report the results of a prospective trial of intraoperative lymphatic mapping and sentinel lymph node identification in patients with head and neck cutaneous melanoma. Methods: Using technetium Tc 99m-labeled sulfur colloid and isosulfan blue, intraoperative lymphatic mapping and sentinel lymph node identification were performed in 43 patients with melanomas of intermediate thickness. After the sentinel lymph nodes were identified in situ, an elective dissection of levels I through V or II through V was performed, based on the location of the primary tumor. The parotid, postauricular, and suboccipital lymphatics were dissected as clinically indicated. The sentinel lymph nodes were isolated ex vivo and evaluated pathologically by serial sectioning, and the accuracy of the lymphatic mapping was determined. Results: Intraoperative lymphatic mapping identified 155 sentinel lymph nodes in 94 nodal basins, with a mean of 3.6 sentinel nodes and 2.2 basins per patient. Sentinel nodes were located in the parotid gland in 19 patients (44%), necessitating superficial parotidectomies, and they were distributed throughout nonadjacent nodal basins in 18 patients (42%). Nine patients (21%) had metastatic disease in 1 or more sentinel nodes, 3 of whom had metastatic disease in a nonsentinel node. No patient who had negative sentinel nodes had a positive nonsentinel node (false-negative incidence, 0). Conclusions: Although intraoperative lymphatic mapping accurately identifies sentinel lymph nodes for head and neck cutaneous melanomas, the multiplicity of these nodes, their widespread distribution, and their frequent location within the parotid gland may preclude sentinel lymph node biopsy in many patients. Therefore, we advocate selective lymphadenectomy of sentinel nodal basins, allowing histological staging of the regional lymphatics with limited morbidity. However, further study is necessary to define the true role of sentinel lymph node identification for head and neck cutaneous melanoma.