Defining pseudoprogression in glioblastoma multiforme

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Clinical Neurology

Background:

• Pseudoprogression is frequently observed in glioblastoma multiforme (GBM) patients undergoing postoperative radiotherapy and temozolomide (RT/TMZ).
• The precise definition, incidence, timing, and impact of pseudoprogression on treatment and outcomes require further clarification.

Purpose of the Study:

• To compare the incidence of pseudoprogression using liberal versus stringent criteria.
• To evaluate pseudoprogression in GBM patients treated before and after the introduction of RT/TMZ therapy.

Main Methods:

• Retrospective review of 136 unselected GBM patients.
• Comparison of pseudoprogression rates based on two distinct sets of diagnostic criteria.
• Analysis of patient cohorts treated with RT/TMZ versus RT alone.

Main Results:

• Pseudoprogression incidence was 12% (stringent criteria) and 23% (liberal criteria) in the RT/TMZ cohort.
• Only one case of pseudoprogression occurred in the RT-alone group.
• Median survival was 28 months for patients with pseudoprogression versus 12 months for those without.

Conclusions:

• The reported incidence of pseudoprogression in GBM patients treated with RT/TMZ is highly dependent on the diagnostic criteria employed.
• Regardless of the criteria used, pseudoprogression did not significantly alter overall patient survival.