Objective: 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.
Methods: 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).
Results: 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).
Conclusion: Increased FDG uptake is observed in medulloblastoma and is correlated negatively with survival.