Gamma-detecting probe used intraoperatively to locate the sentinel lymph node in patients with malignant melanoma

Objective: To assess the usefulness of lymphoscintigraphy and intraoperativ e gamma probe in the detection of sentinel lymph nodes. Design: Prospective open study. Setting: University hospital, Spain. Subjects: 40 patients with malignant melanoma (24 stage MI, 16 stage III). Intervention: The day before operation a lymphoscintigram. with Tc-99m-nano colloid was taken and the first lymph node identified was considered to be the sentinel node. A hand-held gamma probe was used for intraoperative mapp ing. Main outcome measure: Identification of the sentinel node. Results: Sentinel nodes were identified in 39/40 patients (98%). In 24 pati ents with stage I/II disease, 34 sentinel nodes were found (6 invaded and 2 8 clear of melanoma). A total number of 161 regional lymph nodes were harve sted, none of them invaded by melanoma. In 16 patients with stage III disea se, 22 sentinel nodes were located (14 invaded and 8 clear of melanoma). A total of 89 regional lymph nodes were excised in patients with invaded sent inel nodes (44 of which were invaded and 45 clear of disease). 41 lymph nod es were excised from patients with clear sentinel nodes, and all were also clear of melanoma. Conclusions: We conclude that this is a useful technique for the selection of patients with melanoma who may require lymphadenectomy.