[PET scanning for malignant melanoma and positive sentinel node diagnostics]

To illuminate the value of using positron emission tomography (PET) scan as a clinical routine screening procedure for detecting subclinical metastases in melanoma patients with positive sentinel node biopsy, we carried out a retrospective study which included a total of 80 patients.

80 patients with cutaneous malignant melanoma and subclinical lymph node metastases diagnosed by sentinel node biopsy (SNB) were submitted to 18F-fluoro-2-deoxy-D-glucose (FDG) whole-body PET-scanning within 100 days after SNB and wide local excision (WLE). Before FDG-PET scanning, patients were screened conventionally and found to be without evidence of further dissemination. The average follow-up was 30 months (range 7-81 months).

13 patients out of totally 80 patients had a suspicious FDG-PET scan. 4 of these patients (5%) were found true positive by verifying examinations. 67 patients had a negative FDG-PET scan - 4 of these patients developed a clinical recurrence within a period of 6 months after SNB (false negative). This resulted in a sensitivity of 50% and a specificity of 31%.

We conclude that FDG-PET scanning in connection with SNB cannot be recommended as a routine investigation for patients with malignant melanoma and positive SNB.