Magnetic resonance spectroscopy guided radiotherapy boost for patients with glioblastoma.

To assess the feasibility and efficacy of delivering a radiation dose boost to high-risk glioblastoma (GBM) tumor regions, identified using magnetic resonance spectroscopy (MRS) after standard radiotherapy (RT). This retrospective study included patients newly diagnosed with GBM between January 2017 and July 2023. All patients received Intensity-modulated radiotherapy and concurrent temozolomide. Magnetic resonance imaging (MRI) and MRS were performed prior to radiotherapy and after the administration of 60Gy. A biological gross tumor volume (bGTV) was delineated on the simulation CT using the image fusion with the T1 sequence with MRS data after 60Gy. Based on the bGTV volume, patients received an additional 10-20Gy. Survival outcomes were estimated using Kaplan-Meier methods, and Cox regression analysis was applied to explore associations between clinical factors and survival. A total of 114 patients were analyzed. The median patient age was 51 years (range: 18-78 years), and 60.5% were male. Gross total resection was performed in 76 patients prior to RT. IDH1/2 wild-type was identified in 99 patients, and MGMT methylation was present in 40 patients. The median follow-up period was 34.0 months (95% CI, 27.1-40.9 months). The median overall survival (OS) and progression free survival (PFS) were 30.0 months (95%. CI 21.5-38.5 months), and 12.0 months (95%CI 9.5-14.5 months), respectively. Both univariate and multivariate analyses showed that the type of surgical resection and IDH1/2 mutation status were significantly associated with OS and PFS. Headache and fatigue were the most frequently reported symptoms. Delivering a RT boost to high-risk tumor regions identified by MRS after standard RT is feasible in patients with GBM and demonstrate acceptable toxicity. Further prospective clinical trials are warranted to confirm these findings.