Changes in serial magnetic resonance spectroscopy predict outcome in high-grade glioma during and after postoperative radiotherapy.

ABSTRACT

AIM: To determine any correlation between magnetic resonance spectroscopy (MRS) pattern of high-grade glioma before, during, and after radiotherapy (RT) with overall survival (OS) and progression-free survival (PFS). PATIENTS AND METHODS: Twenty-six patients prospectively underwent surgery and RT to 60 Gy. MRS was performed before RT, at week 4 of RT, and 2 months post-RT. Normalized and relative metabolite ratios were evaluated. Patients were grouped according to similar evolving MRS patterns and analyzed for differences in OS and PFS. RESULTS: Significant decreases in tumor choline/N-acetyl-aspartate and normalized choline were observed from baseline to post-RT. After a median follow-up of 22.9 months, patients with >40% decrease in normalized choline from week 4 during RT to 2 months post-RT had a significantly worse median OS (9.1 months vs. not reached, p<0.00001) and PFS (5.8 vs. 19.8 months, p=0.0018). CONCLUSION: The change in normalized choline at 2 months post-RT was highly prognostic for PFS and OS. This may allow more individualized response-based treatment.