INITIAL ASSESSMENT OF POSITRON EMISSION TOMOGRAPHY FOR DETECTION OF NONPALPABLE REGIONAL LYMPHATIC METASTASES IN MELANOMA

Background: The purpose of this pilot study is to determine the feasib ility of positron emission tomography with fluorodeoxyglucose (FDG-PET ) for detection of nonpalpable regional lymph node metastases in patie nts with melanoma. Methods: Adult patients with histologically proven cutaneous melanoma planned to undergo surgical lymphadenectomy for tre atment of nonpalpable subclinical or residual metastatic melanoma in r egional lymph node basin(s) participated. Each patient underwent atten uation-corrected PET imaging of the regional lymph node basin(s) with F18 fluorodeoxyglucose (FDG) followed by complete surgical lymphadenec tomy. FDG-PET scans were interpreted prospectively by an experienced n uclear medicine physician. FDG-PET scan interpretations and histologic results were then correlated. Results: Eleven patients underwent 12 F DG-PET scans followed by 12 operations to clear 14 regional lymph node basins. FDG-PET correctly predicted the presence of metastatic melano ma in seven of seven surgical specimens. FDG-PET scans correctly predi cted the absence of disease in seven of seven histologically negative node basins. Sensitivity was 1.0; specificity was 1.0. Conclusions: Th is study suggests that increased fluorodeoxyglucose uptake in palpably unremarkable regional lymph node basins in patients with melanoma is highly suggestive of metastatic disease. (C) 1997 Wiley-Liss, Inc.