Pseudoprogression in high-grade glioma.

Area of Science:

• Neuro-oncology
• Radiology
• Oncologic Imaging

Background:

• Pseudoprogression is a treatment effect in high-grade glioma, often seen after radiotherapy with temozolomide (TMZ) for glioblastoma multiforme (GBM).
• It presents as contrast enhancement on MRI, mimicking tumor recurrence or radiation necrosis.

Observation:

• Standard MRI with gadolinium contrast cannot reliably differentiate pseudoprogression from true tumor progression or radiation necrosis.
• Medullary pseudoprogression is a rare subentity with limited reported literature.
• Pseudoprogression may be linked to the methylated O(6)-methyl-guanine methyl transferase (MGMT) gene promoter, indicating a positive treatment response.

Findings:

• Misinterpreting pseudoprogression as disease progression can lead to premature discontinuation or alteration of effective therapy.
• Advanced imaging techniques for differentiation are not always accessible.

Implications:

• MRI interpretation in high-grade glioma patients requires caution during the initial six months post-treatment.
• For GBM patients with contrast enhancement but stable clinical status, continuing treatment and scheduling follow-up imaging in 2-3 months is recommended.