Abstract
Objectives: To study the efficacy of gamma-probe radiolocalization of the first draining (sentinel) lymph node (SLN) in stage NO melanoma of the head an neck and to evaluate its potential role in the staging and treatment of this disease. Design: Gamma-probe radiolocalization, a new alternative to blue-dye lymphatic mapping, uses a scintillation (gamma) probe to identify radiolabeled SLNs. In a consecutive sample clinical trial, gamma-probe radiolocalization of the SLN is compared with lymphoscintigraphy and blue- dye lymphatic mapping. Follow-ups ranged from 1.7 years to 4 years, with a mean follow-up of 2.5 years. Setting: Tertiary and private care teaching hospital. Patients: Between June 1993 and November 1995, 23 patients with stage NO intermediate-thickness melanoma of the head and neck were enrolled in this volunteer sample. Interventions: Twenty-four hours prior to surgery, a radioactive tracer was intradermally injected around the circumference of a primary melanoma. Twelve patients also had blue dye injected just prior to surgical resection. Using a handheld gamma probe, radiolabeled lymph nodes were identified and selectively removed with minimal dissection. In patients with nodes with histologic evidence of metastases, a regional lymphadenectomy was performed. Main Outcome Measures: The successful identification of radiolabeled SLNs, the correlation of SLN radiolabeling to lymphoscintigraphy and blue-dye mapping, and the long-term development of regional metastases. Results: Surgeons successfully resected the radiolabeled SLNs in 22 (96%) of 23 patients. The success rate of blue-dye lymphatic mapping was 8 (75%) of 12 patients and lymphoscintigraphy was 20 (91%) of 22 patients. One hundred percent of blue-stained lymph nodes were radiolabaled. The one patient in whom no SLN could be identified developed regional disease at 17 months. Conclusions: Gamma-probe radiolocalization and resection of the radiolabeled SLN is a simple and reliable method of staging regional lymph nodes and determining the need for elective lymphadenectomy.