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

Area of Science:

• Oncology
• Nuclear Medicine
• Diagnostic Imaging

Background:

• Melanoma staging often involves sentinel node biopsy (SNB) to detect lymph node metastasis.
• Subclinical metastases in melanoma patients with positive SNB require accurate detection methods.
• Positron emission tomography (PET) scanning is a potential tool for identifying distant spread.

Purpose of the Study:

• To evaluate the clinical utility of 18F-fluoro-2-deoxy-D-glucose (FDG) whole-body PET-scanning for detecting subclinical metastases.
• To assess the effectiveness of FDG-PET as a routine screening procedure in melanoma patients post-SNB.
• To determine the sensitivity and specificity of FDG-PET in this patient cohort.

Main Methods:

• Retrospective study of 80 melanoma patients with positive SNB and no clinical evidence of dissemination.
• Patients underwent FDG-PET scanning within 100 days of SNB and wide local excision.
• Follow-up averaged 30 months to assess recurrence and verify PET findings.

Main Results:

• 13 out of 80 patients (16.3%) had suspicious FDG-PET scans; 4 were true positives (5% of total).
• 67 patients had negative FDG-PET scans, but 4 (5.9%) developed clinical recurrence within 6 months (false negatives).
• FDG-PET demonstrated a sensitivity of 50% and a specificity of 31% for detecting subclinical metastases.

Conclusions:

• FDG-PET scanning is not a reliable routine investigation for melanoma patients with positive SNB.
• The diagnostic performance (sensitivity and specificity) is insufficient for clinical routine use.
• Alternative or additional staging methods may be necessary for this patient group.