MGMT Promoter Methylation: Prognostication beyond Treatment Response

Area of Science:

• Neuro-oncology
• Molecular Diagnostics
• Surgical Oncology

Background:

• O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation is a key biomarker for glioblastoma (GBM) treatment response.
• Its role in predicting outcomes beyond chemotherapy sensitivity requires further investigation.

Purpose of the Study:

• To explore the impact of MGMT promoter methylation extent on clinical outcomes in GBM patients undergoing surgery with 5-aminolevulinic acid (5-ALA).
• To determine if MGMT promoter methylation functions as a continuous prognostic variable.

Main Methods:

• Retrospective single-centre study of 69 GBM patients operated on with 5-ALA.
• Assessment of demographic, clinical, histology data, and survival rates.
• Correlation analysis of MGMT promoter methylation percentage with preoperative tumor volume, 5-ALA fluorescence, extent of resection (EoR), and survival (PFS, OS).

Main Results:

• Higher MGMT promoter methylation correlated with lower preoperative tumor volume (p=0.003), reduced 5-ALA fluorescence (p=0.041), and increased EoR (p=0.041).
• Elevated MGMT promoter methylation rates were significantly associated with improved progression-free survival (PFS) (p=0.008) and overall survival (OS) (p=0.006), even after adjusting for EoR.
• More adjuvant chemotherapy cycles also predicted longer PFS and OS.

Conclusions:

• MGMT promoter methylation should be viewed as a continuous prognostic factor in GBM.
• Higher methylation percentages are linked to favorable surgical and survival outcomes, independent of chemotherapy sensitivity.
• This finding has implications for personalized treatment strategies in glioblastoma.