Results of NRG-RTOG 9813 Comprehensive Molecular Analysis Demonstrates Importance of Using 2021-WHO Criteria when Classifying Histological Grade 3 Astrocytoma Patients

May 13 2025

Results of a comprehensive molecular analysis of the NRG-RTOG 9813 data, a phase III study testing radiation (RT) and temozolomide (TMZ) versus RT and BCNU/CCNU in anaplastic astrocytoma were recently published in the International Journal of Radiation Oncology, Biology, Physics.

The purpose of this analysis was to determine the features that characterize grade 3 astrocytoma as well as their significance in predicting clinical outcomes for patients. By applying 2021 WHO-defined criteria to the initial trial population, the analysis reclassified 33% of patients to grade 4 astrocytoma, which included a majority of the IDH-wildtype patients. These patients were previously assigned to grade 3 anaplastic astrocytomas. This reclassification allowed researchers to re-evaluate the efficacy of TMZ and RT in specific molecular subgroups that received benefit from the treatment combination, regardless of the patient’s MGMT methylation status.

These results allow clinicians to identify which patients derive greatest benefit from the addition of TMZ or BCNU/CCNU to RT based on MGMT promoter methylation or IDH mutation status. “These results open the door to leverage next generation precision medicine-based approaches for malignant glioma patients” according to Arnab Chakravarti, MD (corresponding author) and Jessica Fleming, PhD (first author).”
Click here to read more on redjournal.org.

Stay current with science. Sign up for our newsletter.

Support NRG Oncology.
Help Our Cause.

We are a leading protocol organizations within the National Clinical Trials Network and we seek to improve the lives of cancer patients by conducting practice-changing, multi-institutional clinical and translational research. Learn More

Donate Today

NRG Oncology Foundation, Inc, is a nonprofit, tax-exempt foundation. Donations to NRG Oncology help us conduct this important mission, and are tax-deductible to the extent permitted by law.