18F]Fluorodeoxyglucose-Positron Emission Tomography in Patients with Medulloblastoma

Abstract

We evaluated the [(18)F]fluorodeoxyglucose (FDG) accumulation during positron emission tomography (PET) in patients with medulloblastoma and examined the relationship of intensity of uptake with patient outcome after the initial scan. Magnetic resonance imaging and FDG-PET scans of brain and spine were used to assess FDG uptake by visual grade (qualitative analysis) and metabolic activity ratios (T(max)/G(mean) and T(max)/W(mean)). Patients were divided into two groups based on either confirmation of tumor by biopsy and/or death resulting from progressive disease after the initial FDG-PET scan (Group A) or no intervention for the suspected lesion shown on magnetic resonance imaging after the initial FDG-PET scan but currently alive without evidence of disease (Group B). Twenty-two patients with either recurrent (n = 21) or newly diagnosed (n = 1) medulloblastoma underwent brain (n = 18) or whole-body (n = 4) FDG-PET scans after magnetic resonance imaging evidence of suspected tumor. The median qualitative analysis was 3 (range, 0-4) in 17 Group A patients compared with 0 (range, 0-1) in 5 Group B patients (P = 0.0003). The mean T(max)/G(mean) and T(max)/W(mean) ratios for 16 Group A patients were 1.3 (range, 0.1-3.8) and 2.10 (range, 0.4-5.2), respectively, compared with 0.80 (range, 0.20-1.5) and 1.3 (range, 0.5-1.9) in 5 Group B patients (P = 0.2 for both parameters, not significant). There was a significant negative correlation between increased FDG uptake and survival. Higher qualitative analysis and T(max)/W(mean) were associated with significantly poorer 2-year overall survival after the initial scan (71% versus 15% for qualitative analysis grade of <3 versus > or =3, P = 0.001; 46% versus 0% for T(max)/W(mean) < or =2.5 versus >2.5, P = 0.004). Increased FDG uptake is observed in medulloblastoma and is correlated negatively with survival.