A RADIOLABELED IODOBENZAMIDE FOR MALIGNANT-MELANOMA STAGING

I-123-N-(di-ethylamino-2-ethyl) 4 iodobenzamide (I-BZA) has been put f orward by the Clermont-Ferrand INSERM U71 group (France) as a tracer f or malignant melanoma. We report on the clinical results obtained in 5 6 studies performed on 48 patients. Whole body scans along with spot v iews were obtained after injection of 185 MBq of I-BZA. The scans were read by three independent observers and correlated to the clinical fi ndings and the other imaging modalities available, taking into account all lesions larger than 1 cm. Patients were classified into two group s on the basis of a post-treatment survey of patients: group I, in com plete remission (24 scans); group II: documented metastases (32 scans) . In group 1, 21 studies were truly negative. However, three studies s howed positive results. Only one turned out to be a false positive (sp ecificity 95%), the other two revealed unknown lesions and modified th e patients' management. In group II, 73% of the known metastases were detected with higher sensitivities (>80%) for eye and orbit, lung and abdomen. One false positive was reported and four new lesions were det ected. I-BZA scintigraphy has the same sensitivity as immunoscintigrap hy with higher specificity and without the risk of xenoimmunization. I t is a useful tool for staging malignant melanoma which can improve pa tient management.