A prospective analysis of 18F-FDG PET/CT in patients with uveal melanoma: comparison between metabolic rate of glucose (MRglu) and standardized uptake value (SUV) and correlations with histopathological features

Purpose

To evaluate whether standardized uptake value (SUV) and/or metabolic rate of glucose (MRglu) are different among epithelioid, mixed, and spindle cell uveal melanomas, as well as between low and high risk melanomas; to correlate ultrasonographic data and metabolic parameters with histopathological features; and to assess the role of ¹⁸F-FDG PET/CT for evaluating prognosis.

Methods

Of 34 eligible patients prospectively enrolled with clinical suspicion of medium/large uveal melanoma, 26 (15 men, mean age 62.8?±?11.8 years) were evaluated. All patients underwent metastatic work-up, 3-D dynamic brain and whole-body ¹⁸F-FDG PET/CT, and surgery.

Results

Of the 26 ocular lesions, 23 showed ¹⁸F-FDG uptake, with a sensitivity of 88 %. MRglu was significantly higher in the epithelioid cell melanomas than in the spindle cell melanomas, as well as in high-risk lesions than in low-risk lesions (p?=?0.01, p?=?0.02, respectively). SUV and MRglu were correlated with histopathological features while ultrasonographic data were not.

Conclusion

MRglu is useful for distinguishing the different cell types in uveal melanoma, as well as high-risk from low-risk lesions, while SUV is not. MRglu provides a more accurate evaluation of glucose consumption, whereas SUV provides only an estimation. In addition, the metabolic parameters correlate with histopathological features, well also reflecting cellular behaviour in ocular malignancy. A longer follow-up is needed to assess the role of ¹⁸F-FDG in evaluating prognosis.