Delayed Pseudoprogression in Glioblastoma Patients Treated With Tumor-Treating Fields

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Medical Physics

Background:

• Glioblastoma multiforme (GBM) treatment often involves radiation therapy and chemotherapy.
• Tumor-treating fields (TTFields) are an established modality for GBM treatment.
• Pseudoprogression, a false sign of disease progression, is a known complication following chemoradiation for GBM.

Observation:

• This report details two glioblastoma patients who experienced radiographic progression six months post-radiation therapy.
• Both patients received radiation, temozolomide maintenance, and TTFields.
• Lesion appearance in these cases occurred later than the typical pseudoprogression window.

Findings:

• One patient's post-resection pathology confirmed treatment effect, diagnosing pseudoprogression.
• The second patient's condition resolved with steroid therapy alone.
• These cases highlight delayed pseudoprogression potentially linked to TTFields therapy.

Implications:

• TTFields may alter plasma cell membrane permeability, potentially increasing gadolinium leakage and mimicking tumor progression.
• Understanding delayed pseudoprogression is crucial for accurate treatment response assessment in GBM patients.
• Further research is needed to elucidate the mechanisms of TTFields-induced delayed pseudoprogression and optimize therapeutic strategies.