Today's treatment starts with surgical removal of as much of the tumor as possible. Following a brief recovery period, patients are typically placed on the standard of care, first line treatment of radiation plus concurrent and adjuvant temozolomide. Periodic imaging is ordered to monitor tumor status. Upon progression, a number of second-line treatment options may be pursued, including protocol driven or investigational approaches. Some centers are also incorporating additional treatments into first line care.
The Need for DecisionDx-GBM
Today, GBM is diagnosed using traditional histopathology techniques. However, tissue staining and microscopic visualization does not discern tumor biology which is important in determining prognosis of an individual patient.
It is known that some GBM tumors exhibit a good, sustained response to first line treatment while others appear refractory. However, histopathologic diagnosis of GBM itself does not enable prospective identification of these two groups.
The DecisionDx-GBM assay was developed to fulfill this need. Prospective risk-stratification allows for more individualized treatment options to be considered early on in diagnosis.
It is our hope that the additional information provided from DecisionDx-GBM, in concert with other clinical information, will become a valuable component of the comprehensive baseline evaluation.
What is DecisionDx-GBM?
The DecisionDx-GBM test is a robust metagene expression assay that determines the molecular signature of a GBM tumor. This signature enables prospective stratification of the tumor's response to the first-line standard of care treatment for GBM - radiation with concurrent and adjuvant temozolomide (Colman, et al, 2010).
Specifically, our most recent clinical update found an overall median survival of 71 weeks for the entire GBM population. However, significant differentiation in progression-free survival and overall survival occur between the long-term responder group and the short-term or refractory responder group (median overall survival: 377 weeks vs 56 weeks; p<0.0001).
Through multivariate analysis, DecisionDx-GBM has been shown to be independent of age, performance score (p=0.0003), and MGMT methylation (p=0.0055). In the same analysis, MGMT methylation was not found to be independent of DecisionDx-GBM (p=0.0602).