Incidence of nonlocalization of sentinel lymph nodes using preoperative lymphoscintigraphy in 74 consecutive head and neck melanoma and Merkel cell carcinoma patients.
Academic Article
Overview
abstract
INTRODUCTION: Lymphatic drainage pathways in the head and neck region are more variable than in any other location of the body. Occasionally, head and neck lymphoscintograms fail to identify a definitive lymphatic drainage pattern, making preoperative and intraoperative identification of sentinel nodes very difficult. The purpose of this study was to determine the incidence of nonlocalization on lymphoscintigraphy of sentinel nodes in patients with head and neck cutaneous malignancies. METHODS: A retrospective chart review was conducted of a single surgeon's (WKS) 135 consecutive head and neck melanoma and Merkel cell cancer patients from August 1997 to August 2002. In all cases. technetium-99m sulfur colloid was the radioactive tracer used by the nuclear medicine department to perform the lymphoscintograms. RESULTS: Of the 135 patients, 74 underwent preoperative lymphoscintigraphy in preparation for performing a sentinel lymph node biopsy. Of these 74 patients, 5 (6.8%) were found to have nonlocalization of a sentinel node(s). Of the 5 patients who failed to localize, 3 had primary lesions near the midline scalp, while 2 had primary lesions located on the cheek. Two of the 5 patients underwent reinjection of the radioisotope by the treating surgeon (WKS) but failed to further localize the radiotracer. All 5 patients went on to have wide local excision of the primary cancer on the day of the lymphoscintogram, as well as undergoing intraoperative examination of all head and neck nodal basins with a handheld gamma detector. No focal areas of radiation were identified and no lymph nodes were biopsied. To date, 1 patient has developed distant metastases and has succumbed to her disease. The remaining 4 patients are free of disease. CONCLUSION: In a series of 135 consecutive patients with head and neck cutaneous malignancies, 74 of whom were treated with preoperative lymphoscintograms, a nonlocalization rate of 6.8% was found. This is a significant rate of nonlocalization and reflects either the inherent difficulty in imaging the head and neck region and/or the possible rapid rate of dye washout via multiple lymphatic drainage pathways that exist in this location.
