Iotandium-111 pentetreotide scintigraphy and CT scans after 3 years in the follow-up of patients with malignant melanoma.

Somatostatin receptor scintigraphy (SRS) has been used for the detection of neuroendocrine tumors. Melanoma is a malignant tumor of melanocytes, considered to derive from the neural crest. As the prognosis of melanoma is very poor, early detection of the disease, of recurrences and of distal metastases, is important. The aim of our study was to evaluate the clinical impact of indium-111-diaethyleno triamino pentaacetic acid-d-phe1-octreotide ((111)In-DTPA-octreotide or octreoscan or (111)In-O) in the management of melanoma patients after first diagnosis and first surgery and during three years of follow-up. We have studied 35 patients 20 female and 15 male, with histological proven melanoma. Scintigraphic images with single photon emission tomography gamma-camera (Millenium GE-USA) were performed after the administration of 220MBq (111)In-O. The scintigraphic data were compared to axial computerized tomography (CT). Patients were followed for 3 years after the initial diagnosis and surgery. Our results showed that during the 3 years follow-up period, 26/35 patients had a clinical recurrence. Twenty of them had positive (111)In-O scans with 56 lesions mainly metastatic, while 6 had negative scans. The CT scans showed only 31/56 lesions. In conclusion, SRS with (111)In-O, for diagnosing metastases from malignant melanoma, showed a sensitivity and specificity of 87% and 94% respectively and within the 3 years of follow-up, the stage of melanoma and surgical strategies were modified by 48% and 32%, respectively. Twenty five tumor sites, unsuspected by CT were visualized by (111)In-O.