Glioblastoma, the most common primary malignant brain tumor among adults, is a highly angiogenic and deadly tumor. Angiogenesis in glioblastoma, driven by hypoxia-dependent and independent mechanisms, is primarily mediated by vascular endothelial growth factor (VEGF), and generates blood vessels with distinctive features. The outcome for patients with recurrent glioblastoma is poor because of ineffective therapies. However, recent encouraging rates of radiographic response and progression-free survival, and adequate safety, led the FDA to grant accelerated approval of bevacizumab, a humanized monoclonal antibody against VEGF, for the treatment of recurrent glioblastoma in May 2009. These results have triggered significant interest in additional antiangiogenic agents and therapeutic strategies for patients with both recurrent and newly diagnosed glioblastoma. Given the potent antipermeability effect of VEGF inhibitors, the Radiologic Assessment in Neuro-Oncology (RANO) criteria were recently implemented to better assess response among patients with glioblastoma. Although bevacizumab improves survival and quality of life, eventual tumor progression is the norm. Better understanding of resistance mechanisms to VEGF inhibitors and identification of effective therapy after bevacizumab progression are currently a critical need for patients with glioblastoma.
David A. Reardon, Scott Turner, Katherine B. Peters, Annick Desjardins, Sridharan Gururangan, John H. Sampson, Roger E. McLendon, James E. Herndon II, Lee W. Jones, John P. Kirkpatrick, Allan H. Friedman, James J. Vredenburgh, Darell D. Bigner and Henry S. Friedman
Louis Burt Nabors, Jana Portnow, Mario Ammirati, Joachim Baehring, Henry Brem, Nicholas Butowski, Robert A. Fenstermaker, Peter Forsyth, Jona Hattangadi-Gluth, Matthias Holdhoff, Steven Howard, Larry Junck, Thomas Kaley, Priya Kumthekar, Jay S. Loeffler, Paul L. Moots, Maciej M. Mrugala, Seema Nagpal, Manjari Pandey, Ian Parney, Katherine Peters, Vinay K. Puduvalli, John Ragsdale III, Jason Rockhill, Lisa Rogers, Chad Rusthoven, Nicole Shonka, Dennis C. Shrieve, Allen K. Sills Jr, Lode J. Swinnen, Christina Tsien, Stephanie Weiss, Patrick Yung Wen, Nicole Willmarth, Mary Anne Bergman and Anita Engh
For many years, the diagnosis and classification of gliomas have been based on histology. Although studies including large populations of patients demonstrated the prognostic value of histologic phenotype, variability in outcomes within histologic groups limited the utility of this system. Nonetheless, histology was the only proven and widely accessible tool available at the time, thus it was used for clinical trial entry criteria, and therefore determined the recommended treatment options. Research to identify molecular changes that underlie glioma progression has led to the discovery of molecular features that have greater diagnostic and prognostic value than histology. Analyses of these molecular markers across populations from randomized clinical trials have shown that some of these markers are also predictive of response to specific types of treatment, which has prompted significant changes to the recommended treatment options for grade III (anaplastic) gliomas.