LOCL-16 IMPACT OF MGMT PROMOTER METHYLATION STATUS ON TUMOR DYNAMICS DURING WEEKLY ADAPTIVE RADIOTHERAPY FOR GLIOBLASTOMA

ABSTRACT: Abstract

PURPOSE

Adaptive MRI-guided radiotherapy (RT) on a 1.5T-MR-Linac using reduced clinical target volumes (CTV) of 5mm instead of the 15mm standard for glioblastoma (GBM) is currently being evaluated on the UNITED clinical trial (NCT04726397). We explored the morphological changes that occur during adaptive RT with concurrent temozolomide between tumors with MGMT promotor methylation (MGMT-m) vs. unmethylation (MGMT-um).

METHODS

Thirty patients with IDH-wildtype GBMs were treated with 60Gy in 30 (n=12) or 40Gy in 15 fractions (n=18) (Fx). The CTV included a 5mm expansion on the gross tumor volume (GTV) +/- FLAIR hyperintense areas-at-risk and a 3mm planning target volume. Planning was performed on a pre-treatment reference MRI (FxRef) followed by weekly on-line adap

SUBMITTER:  

PROVIDER: S-EPMC9354172 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature