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

ABSTRACT

OBJECTIVE: To assess the usefulness of lymphoscintigraphy and intraoperative 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 I/II, 16 stage III). INTERVENTION The day before operation a lymphoscintigram with 99mTc-nanocolloid was taken and the first lymph node identified was considered to be the sentinel node. A hand-held gamma probe was used for intraoperative mapping. MAIN OUTCOME MEASURE: Identification of the sentinel node. RESULTS: Sentinel nodes were identified in 39/40 patients (98%). In 24 patients with stage I/II disease, 34 sentinel nodes were found (6 invaded and 28 clear of melanoma). A total number of 161 regional lymph nodes were harvested, none of them invaded by melanoma. In 16 patients with stage III disease, 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 sentinel nodes (44 of which were invaded and 45 clear of disease). 41 lymph nodes 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.