The study was published as a preprint on researchsquare.com and has not yet been peer reviewed.
Key Takeaway
The response of IDH-wild type recurrent glioblastoma to vascular endothelial growth factor (VEGF) inhibitors can be predicted by the pretreatment MRI contrast enhancing pattern.
With predominantly contrast enhancing lesions, bevacizumab prolongs progression-free survival (PFS) compared to the alkalizing agent temozolomide.
With predominantly nonenhancing lesions, bevacizumab results in shorter PFS compared to temozolomide.
Why This Matters
Bevacizumab is increasingly being used for recurrent glioblastoma, but tumor responses vary substantially between patients.
The contrast enhancing pattern on conventional pretreatment MRI is a reliable and reproducible imaging biomarker to select patients for treatment with bevacizumab.
Study Design
Of the 65 patients with recurrent glioblastoma, 46 received bevacizumab and 19 received temozolomide as their secondary treatment.
Forty-five patients were categorized by two neuroradiologists as having contrast enhancing lesion (CEL) dominant disease and 20 as having nonenhancing lesion (NEL) dominant disease.
Response to treatment was correlated to the contrast enhancing pattern on pretreatment MRI.
Key Results
Bevacizumab was associated with longer PFS in the CEL dominant group (P=.031), and temozolomide was associated with longer PFS in the NEL dominant group (P=.022).
On univariate analysis, bevacizumab was associated with longer PFS in the CEL group (hazard ratio [HR], 0.418; P=.038) but shorter PFS in the NEL dominant group (HR, 3.386; P=.031)
Quantitative analysis revealed cutoffs for the proportion of solid-enhancing tumor of 13.7% for the CEL group and 4.3% for the NEL group.
Limitations
The study was retrospective with small patient numbers.
Radiographic progression was not confirmed by histology.
MRI did not incorporate advanced techniques, such as perfusion-weighted imaging, to assess progression and treatment response.
Disclosures
No funding source was reported, and the investigators did not report any financial conflicts.
This is a summary of a preprint research study, “Contrast Enhancing Pattern on Pre-Treatment MRI predicts Response to Anti-Angiogenic Treatment in Recurrent Glioblastoma: Comparison of Bevacizumab and Temozolomide Treatment.” The study, which appeared on researchsquare.com on January 10, has not been peer reviewed.
M. Alexander Otto is a physician assistant with a master’s degree in medical science. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape and is an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.
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