Pretreatment MRI Predicts Response to VEGF Inhibitor in Recurrent Glioblastoma

M. Alexander Otto, MMS, PA

January 21, 2022

The study was published as a preprint on researchsquare.com and has not yet been peer reviewed.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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