The effect of fluorine-18 fluorodeoxyglucose positron emission tomography on the management of cutaneous malignant melanoma

Purpose: To assess the effect of positron emission tomography (PET) with fl uorine-18 fluorodeoxyglucose (FDG) on the treatment of patients with cutane ous malignant melanoma. Materials and Methods: We retrospectively reviewed the medical records of 3 8 patients with newly diagnosed (n = 25) and recurrent (n = 13) cutaneous m elanoma who were referred for evaluation with FDG PET imaging at our instit ution. We compared the PET findings with computed tomography (CT), which wa s available in 21 (55%) patients, and tabulated the changes in the diagnost ic evaluation and therapeutic management that were prompted by PET during a follow-up period of 10 to 36 months. Results: Compared with PET, the extent of disease was underestimated by CT in 5 (13%) patients. Planned surgical resection of metastases was canceled in two of these patients. In another patient, surveillance PET detected an unsuspected hypermetabolic abdominal mass that was noted on a subsequent CT to arise from the small bowel. The mass was found to be jejunal metastatic melanoma at the time of resection, Overall, PET influenced surgical manage ment in 3 (8%) patients, but it did not affect the wait-and-watch strategy or decision to initiate immunotherapy in the others. Conclusions: FDG PET contributes important information not provided by CT a nd has a substantial effect on the clinical management of patients with mal ignant melanoma.