Prognostic value of the standardized uptake value for 18F-fluorodeoxyglucose in patients with stage IIIB melanoma

Purpose

FDG PET/CT is an excellent tool to detect melanoma metastases and also allows quantification of FDG uptake using standardized uptake value (SUV). The aim of this study was to prospectively investigate the potential prognostic value of SUV for disease-free survival (DFS) and disease-specific survival (DSS) for patients with stage IIIB melanoma.

Methods

From November 2003 to March 2008, all consecutive patients were included in the present study. Inclusion criteria were: palpable, histology- or cytology-proven lymph node metastases of melanoma, and referred to the University Medical Centre Groningen for FDG PET and CT examination. Patients without distant metastases were evaluated. Multivariable survival analysis was performed to determine whether SUV was associated with DFS and DSS (Cox proportional hazard analysis).

Results

In 80 patients (without distant metastases, 65?%) SUV could be measured. Overall 5-year DFS was 41?% (95% CI 26–56?%) and 24?% (95% CI 12–38?%) in patients with a low and high SUVmean (p?=?0.02), respectively. Overall 5-year DSS was 48?% (95% CI 31–62?%) and 30?% (95% CI 17–45?%) in patients with a low and high SUVmean (p?=?0.04), respectively. In the multivariable analysis, SUVmean was associated with DFS (hazard ratio 1.7; p?=?0.048), but was not associated with DSS (hazard ratio 1.6; p?=?0.1). The number of positive nodes, extranodal growth and gender were also associated with survival.

Conclusion

FDG uptake in clinically overt nodal melanoma metastases is inversely associated with DFS. Univariate analysis showed an association with DSS. However, after adjustment for potential confounders this association was no longer significant. If these findings are confirmed in larger studies, SUVmean could potentially be used (in addition to the number of positive nodes, tumour size and extranodal growth) as a factor in deciding on adjuvant systemic treatment.