Prognostic value of choline and creatine in WHO grade II gliomas

Abstract

The purpose of this study was to evaluate whether proton magnetic resonance spectroscopy ((1)H-MRS) predicts survival time, tumor progression, and malignant transformation in patients with WHO grade II gliomas. (1)H-MRS and MR imaging (MRI) were performed before surgery in 45 patients with histologically proven WHO grade II gliomas. Metabolite concentrations of choline-containing compounds (Cho) and creatine/phosphocreatine (tCr) were normalized to contralateral brain tissue. Spectroscopic data as well as the extent of tumor resection, contrast enhancement, size and histopatholocical type of the tumor, age, sex, and first neurological symptoms of the patients were analyzed for survival, tumor progression, and malignant transformation for a follow-up period of 1 to 5 years. The normalized tCr of WHO grade II gliomas was a significant predictor for tumor progression (p = 0.011) and for malignant tumor transformation (p = 0.016). Further, contrast enhancement of the tumor (p = 0.014) at the time of diagnosis was significant for malignant tumor transformation and extent of tumor resection for the tumor progression (p = 0.007). All other parameters failed to predict any of the three endpoints. Normalized values of tCr in WHO grade II gliomas may have prognostic implications for this group of gliomas. As a rule of the thumb, low-grade gliomas with decreased tCr (relative tCr values below 1.0) may show longer progression-free times and later malignant transformation than low-grade gliomas with regular or increased tCr values.