Monitoring temozolomide treatment of low-grade glioma with proton magnetic resonance spectroscopy

Abstract

Assessment of low-grade glioma treatment response remains as much of a challenge as the treatment itself. Proton magnetic resonance spectroscopy ( 1 H-MRS) and imaging were incorporated into a study of patients receiving temozolomide therapy for lowgrade glioma in order to evaluate and monitor tumour metabolite and volume changes during treatment. Patients (n ¼ 12) received oral temozolomide (200 mg m À2 day À1 ) over 5 days on a 28-day cycle for 12 cycles. Response assessment included baseline and three-monthly magnetic resonance imaging studies (pretreatment, 3, 6, 9 and 12 months) assessing the tumour size. Short (TE (echo time) ¼ 20 ms) and long (TE ¼ 135 ms) echo time single voxel spectroscopy was performed in parallel to determine metabolite profiles. The mean tumour volume change at the end of treatment was À33% (s.d. ¼ 20). The dominant metabolite in long echo time spectra was choline. At 12 months, a significant reduction in the mean choline signal was observed compared with the pretreatment (P ¼ 0.035) and 3-month scan (P ¼ 0.021). The reduction in the tumour choline/water signal paralleled tumour volume change and may reflect the therapeutic effect of temozolomide.

Multimodal Imaging to Delineate Tumor Heterogeneity in Cerebral Gliomas

“…There are new promising approaches using other than the mentioned metabolites such as glycine or myoinositol for glioma grading [37] or using MRS as a method for evaluate therapy response imgliomas [38]- [40]. In addition, the inclusion of other than the mentioned methods, such as diffusion weighted imaging seems to be a useful tool in tumor grading [41].…”

Imaging Techniques in Brain Tumor

“…The sensitivity, accuracy and specificity of discriminating high-grade tumor or low-grade tumor are 100%, 96% and 86% respectively. In assurance of tumor grading, the Cho, Lac, Lip, NAA, Cr and mI can provide us lots of useful information (Murphy et al, 2004). Within the high-grade tumors, the higher Cho, Lac, Lip and mI can be detected, but NAA and Cr often show a decreasing form.…”

MR in oncology drug development

“…Abnormalities in 31 P spectra from tumors are not completely specific for malignancy, as they also occur in other diesase processes; however a number of studies have addressed the diagnostic potential for MRSI, particularly in brain, prostate and breast tumors (49)(50)(51). For assessment of anti-cancer therapeutic effects, changes in high-energy phosphate levels and metabolic spectra have been shown to occur with radio-and chemotherapy of tumors (52,53). The spectroscopic alterations are often seen before any reduction in tumor size can be detected, but there is heterogeneity in response characteristics.…”