Clinical applications of fluorodeoxyglucose--positron emission tomography in the management of malignant melanoma.

PURPOSE OF REVIEW: Malignant melanoma is the seventh most common newly diagnosed cancer among Americans. In most cases, melanoma is curable by means of surgical excision if diagnosed in early stages of the disease. The prognosis is linked directly to the initial stage at the time of diagnosis. Early diagnosis and accurate disease staging is important for appropriate treatment planning. This review focuses on clinical applications of positron emission tomography (PET) using F-fluorodeoxyglucose (FDG) in the management of patients with malignant melanoma.

RECENT FINDINGS: Many investigators have studied the role of FDG-PET in the management of malignant melanoma. PET has been shown to have a strong role in detection of metastatic disease. FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. It is more sensitive than computed tomography (CT) for detection of metastatic lesions in skin, lymph nodes, and abdomen. Despite the overall superiority of FDG-PET in the detection of melanoma metastases, it has limitations in detection of early-stage disease (stage I-II), small lung nodules, and brain metastases. Most of the false-negative FDG-PET results are due to micrometastases and lesions small than 10 mm. False-positive FDG-PET results are due to postsurgical inflammation, other inflammatory lesions, and some benign tumors.

SUMMARY: FDG-PET is a metabolic, noninvasive imaging modality for detecting distant metastatic and recurrent melanoma. FDG-PET is of limited use in patients with early-stage disease and cannot replace sentinel node biopsy, which is much more sensitive in detecting microscopic lymph node metastases.