[Selective regional lymphadenectomy in malignant melanoma using a gamma probe]

The accurate excision of the first tumour draining lymph node (sentinel lymph node SLN) can prevent extended surgery intervention in many patients with malignant melanoma. The aim of our study was to test the practicability of the SLN dissection using a gamma probe. In a total of 52 patients, mostly with high-risk melanoma, a selective lymph node dissection was performed. We injected intracutuneously about 50 MBq Tc-99m colloid around the tumour or scar followed by dynamic and late static imaging. The site of SLN was localized with a gamma probe and marked on the skin. This was followed by the dissection of the SLN using the gamma probe. In 51 of 52 patients the SLN could be found intraoperatively using the gamma probe. The SLN contained microscopic metastases in 13 patients (24%). The rate of positive SLN was 40% in patients with high-risk melanoma (Breslow thickness more than 1.5 mm). In case of positive SLN a second surgical intervention with radical lymph node dissection was followed. We conclude that dynamic lymphscintigraphy and the selective lymph node dissection using the gamma probe is a simple and minimally invasive method which can improve the survival probability in patients with micrometastases.