Total lesion glycolysis by ¹⁸F-FDG PET/CT is a reliable predictor of recurrence in cutaneous malignant melanoma

Objectives This study was performed to evaluate the prognostic relevance of total lesion glycolysis (TLG) measured by F-18 FDG PET/CT in patients with primary cutaneous malignant melanoma (CMM).

Methods This is a retrospective review (Mar 2005 to Nov 2010) of forty-three patients with histologic diagnosis of CMM who underwent pretreatment F-18 FDG PET/CT. PET parameters [SUVmax, metabolic tumor volume (MTV, cm³) and total lesion glycolysis (TLG)] of primary tumor were measured. Clinical variables such as age, sex, clinical stage, and location and thickness of primary lesion, and existence of ulceration were also assessed. Univariate and multivariate analyses for disease free survival (DFS) were performed by Kaplan-Meier method and Cox proportional hazards models.

Results SUVmax, MTV, and TLG were found to be significantly higher in patients with recurrence (4.5 ± 2.9; 4.6 ± 3.8; 9.8 ± 8.7) than patients without recurrence (2.1 ± 1.6; 2.8 ± 1.5; 3.8 ± 3.3, p<0.001). The optimal cut-off values for the DFS determined using a receiver-operating characteristic (ROC) curve were 1.7 for SUVmax, 2.84 for TLG, however, MTV was not statistically significant on ROC curve analysis. The DFS rate among the 43 patients was 72%. On univariate analysis, ulceration of primary lesion (p = 0.004), stage ≥ III (p = 0.017), SUVmax > 1.7 (p = 0.001), and TLG > 2.84 (p = 0.005) affected the DFS, whereas others (age, sex, primary lesion site, and thickness of primary lesion) did not. However, none of them was statistically significant on multivariate analysis.

Conclusions SUVmax and TLG of primary lesion on pretreatment F-18 FDG PET/CT significantly affected outcome in CMM patients. TLG could be used as a good surrogate marker for the prediction of DFS in CMM patients.