[Prognostic value of PET using 11C-methionine in patients with untreated cerebral gliomas]

We evaluated the prognostic role of positron emission tomography (PET) with 11C-methionine in adults with untreated supratentorial glioma. Histopathologic grading and clinical follow-up data were available from 147 patients with low-grade (n=74) and high-grade gliomas (n=73). Follow-up was conducted until the last clinical contact (n=79) or until death (n=68). The 11C-methionine uptake index (UI) was calculated as the tumor hot spot-to-normal cortex uptake ratio. In the univariate analysis the statistical support from clinical, histological, and PET parameters was estimated using Kaplan-Meier method and log-rank test. For all glioma patients age (<40 or > or = 40 years), astrocytoma histopathology and WHO grading class (low versus high), extent of the increased 11C-methionine uptake (<6 cm or > or = 6), were found to be significant predictors of survival by univariate analysis. For all grades of gliomas UI higher than 2.0 was statistically associated with a shorter survival (p=0.00001). Patient sex, glioma location, pattern of the 11C-methionine uptake were not significantly predictive. In the most patients UI was closely associated with glioma histopathology. However separate analysis of astrocytoma subgroups showed that PET with "C-methionine was a more reliable prognostic factor in case of conflict between metabolic characteristic and histopathology findings. A high uptake of 11C-methionine and large extent of increased 11C-methionine accumulation were statistically associated with a poor survival time. Results showed that PET with 11C-methionine may be useful for determinating the prognosis of patients with primary glioma and this information can provide aid in making treatment decision.