Nimg-77. Impact of Post-surgical Enhancing Tumor Volume and T2/flair Volume on the Survival Impact of Bevacizumab in Nrg Oncology/rtog 0825
Year: 2017
Type: article
Abstract: RTOG 0825 randomized 621 newly-diagnosed glioblastoma patients to treatment with or without bevacizumab, in addition to standard-of-care radiotherapy plus concurrent/adjuvant temozolomide. No significant difference was seen between the treatment arms in overall survival (OS), and the difference in progression free survival (PFS) did not meet the pre-defined statistical margin. We evaluated the impact of post-surgical MRI-determined residual tumor on outcomes. 431 (69.4%) patients had post-operative T1 MRIs (with and without gadolinium) and 517 (83.2%) had T2 or FLAIR images. Volumetric segmentation was performed to calculate residual enhancing (T1Gd-T1) volume (rEV) and T2/FLAIR volume (rT2FV). Multivariable analyses were performed using Cox models with pretreatment characteristics and treatment as covariates. Median post-operative, pre-treatment rEV was 2.8 cc (range 0.0-79.6 cc) and rT2FV volume was 52.3 cc (0.0-279. 8 cc). Neither age nor MGMT methylation were predictors of rEV or rT2FV. Ninety-four (21.8%) patients had an imaging-complete resection of enhancing tumor (rEV=0.0). We did not detect a significant difference in OS or PFS for an imaging-complete resection. Notably, however, a rEV <= 2.8 cc was associated with better OS (HR=1.37, p=0.008 Log-rank) and PFS (HR=1.25, p=0.04 Log-rank). rT2FV had no detectable impact on OS or PFS, but there were significant interactions affecting outcomes between treatment arms and rT2FV. Patients with a less than median rT2FV had improved PFS with bevacizumab (HR=0.64, p=0.001). Surprisingly, patients with a higher than median rT2FV had poorer OS with bevacizumab (HR=1.42, p=0.02). These prospective data demonstrate the benefits associated with minimizing residual contrast-enhancing tumor in glioblastoma. MGMT status did not appear to independently determine residual tumor volume after surgery. Finally, bevacizumab appears to provide PFS benefit in patients with smaller rT2FV, and diminishes OS in patients with larger rT2FV. Supported by U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC) from the NCI and Genentech.
Source: Neuro-Oncology
Authors: Michael Vogelbaum, Kristin Swanson, Peixin Zhang, Daniel Cahill, Andrea Hawkins-Daarud, Mark R Gilbert, Gustavo De Leon, Cassandra Rickertsen, Lauren Kunkel, Wenyin Shi, Marta Penas-Prado, Emad Youssef, Hui-Kuo Shu, Merideth Wendland, John Suh, John Keech, Steven Howard, Vesna Kaluza, Minhee Won, Minesh P Mehta
Institutions: Cleveland Clinic, Mayo Clinic, Mayo Clinic Hospital, NRG Oncology, Massachusetts General Hospital, National Institutes of Health, National Cancer Institute, Thomas Jefferson University, The University of Texas MD Anderson Cancer Center, Barrow Neurological Institute, Emory University, Texas Oncology, Intermountain Medical Center, University of Wisconsin–Madison, UW Health University Hospital, Sparrow Hospital, Michigan Cancer Research Consortium
Language: English
Subfield: Genetics
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2767804768