LOCALIZATION OF REGIONAL LYMPH-NODES IN MELANOMAS OF THE HEAD AND NECK

Objectives: To study the efficacy of gamma-probe radiolocalization of the first draining (sentinel) lymph node (SLN) in stage N0 melanoma of the head and neck and to evaluate its potential role in the staging a nd 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 cl inical trial, gamma-probe radiolocalization of the SLN is compared wit h 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. Settin g: Tertiary and private care teaching hospital. Patients: Between June 1993 and November 1995, 23 patients with stage N0 intermediate-thickn ess melanoma of the head and neck were enrolled in this volunteer samp le. Interventions: Twenty-four hours prior to surgery, a radioactive t racer was intradermally injected around the circumference of a primary melanoma. Twelve patients also had blue dye injected just prior to su rgical resection. Using a handheld gamma probe, radiolabeled lymph nod es were identified and selectively removed with minimal dissection. In patients with nodes with histologic evidence of metastases, a regiona l lymphadenectomy was performed. Main Outcome Measures: The successful identification of radiolabeled SLNs, the correlation of SLN radiolabe ling to lymphoscintigraphy and blue-dye mapping, and the long-term dev elopment of regional metastases. Results: Surgeons successfully resect ed the radiolabeled SLNs in 22 (96%) of 23 patients. The success rate of blue-dye lymphatic mapping was 8 (75%) of 12 patients and lymphosci ntigraphy was 20 (91%) of 22 patients. One hundred percent of blue-sta ined lymph nodes were radiolabeled. The one patient in whom no SLN cou ld be identified developed regional disease at 17 months. Conclusions: Gamma-probe radiolocalization and resection of the radiolabeled SLN i s a simple and reliable method of staging regional lymph nodes and det ermining the need for elective lymphadenectomy.