Fluorodeoxyglucose-positron emission tomography and sentinel lymph node biopsy in staging primary cutaneous melanoma

We report the value of sentinel lymph node (SLN) biopsy and fluorodeoxyglucose-positron emission tomography (FDG-PET) in relation to SLN biopsy in staging primary cutaneous melanoma.

Fifty-five patients with primary cutaneous melanoma >1.0 mm. Breslow thickness and no palpable regional lymph nodes underwent a FDG-PET scan before SLN biopsy.

SLN's were retrieved in 53 patients. Melanoma metastases were found in the SLN of 13 patients. FDG-PET detected the lymph node metastases in two of the 13 patients with SLN metastases. In five patients FDG accumulation was recorded in a regional lymph node basin, while no tumour positive SLN was found. In eight patients FDG-PET showed increased activity at a site of possible distant metastasis. Metastatic disease was confirmed in one patient. No explanation for the positive FDG-PET result could be found in five cases.

FDG-PET should not be considered in this group. SLN biopsy reveals regional metastases that are too small to be detected by FDG-PET. The prevalence of distant metastases is too small to justify routine use of FDG-PET.