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Updated: Jun 19, 2026
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Translational Orthotopic Models of Glioblastoma Multiforme
Published on: February 17, 2023
Population-based study of pseudoprogression after chemoradiotherapy in GBM
Gloria B Roldán1, James N Scott, John B McIntyre
1Department of Oncology, Tom Baker Cancer Centre, Alberta Cancer Board, Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada.
Summary
Radiographic pseudoprogression is common in glioblastoma multiforme (GBM) patients after chemoradiotherapy. Continuing temozolomide (TMZ) treatment can lead to stability or improvement, suggesting it should not be prematurely stopped.
Area of Science:
- Neuro-oncology
- Radiation Oncology
- Medical Imaging
Background:
- Chemoradiotherapy with temozolomide (TMZ) is standard for glioblastoma multiforme (GBM).
- Radiographic pseudoprogression, a transient deterioration, can occur after treatment.
- The natural history of pseudoprogression in GBM is not well understood.
Purpose of the Study:
- To determine the incidence of radiographic pseudoprogression in GBM patients.
- To investigate the relationship between pseudoprogression, patient outcomes, and MGMT promoter methylation.
- To evaluate the impact of continuing adjuvant temozolomide (TMZ) in cases of apparent progression.
Main Methods:
- Retrospective analysis of a population-based cohort of GBM patients.
- Evaluation of initial MRI scans post-concurrent chemoradiotherapy.
- Assessment of outcomes, including median survival, in relation to pseudoprogression and MGMT methylation status.
Main Results:
- 58% of GBM patients showed radiographic progression on initial MRI after concurrent treatment.
- Of those with progression, 50% experienced radiographic pseudoprogression with continued adjuvant temozolomide (TMZ).
- Median survival was significantly better for patients with pseudoprogression (14.5 months) versus true progression (9.1 months).
Conclusions:
- Radiographic pseudoprogression is a significant phenomenon in GBM patients treated with chemoradiotherapy.
- Physicians should consider continuing adjuvant temozolomide (TMZ) in GBM patients with apparent early progression.
- Up to 50% of GBM patients with initial radiographic progression may experience stability or improvement with continued TMZ therapy.
