Meningioma treated with interferon-alpha, evaluated with [(11)C]-L-methionine positron emission tomography

Area of Science:

• Neuro-oncology
• Medical imaging
• Pharmacodynamics

Background:

• Meningiomas are primary brain tumors often requiring multimodal treatment.
• Assessing treatment efficacy in recurrent or inoperable meningiomas is clinically significant.
• Interferon-alpha (IFN-alpha) is a potential therapeutic agent for meningioma management.

Purpose of the Study:

• To evaluate the efficacy of IFN-alpha in meningioma patients with residual, recurrent, or inoperable tumors.
• To determine if [(11)C]-L-methionine positron emission tomography (PET) can predict treatment response.
• To assess the utility of PET for guiding IFN-alpha dosage and long-term treatment strategies.

Main Methods:

• Twelve meningioma patients received daily subcutaneous IFN-alpha (1.5-5 million IU).
• [(11)C]-L-methionine PET, CT, and/or MRI were performed before and during treatment.
• A tumor-to-cerebellum/cortex uptake ratio was calculated to estimate methionine accumulation and tumor proliferation.

Main Results:

• PET showed a mean relative reduction in uptake ratio (MRelR) of 22.3% during IFN-alpha treatment.
• Nine responders achieved a mean MRelR of 30.4%, while three non-responders had a mean MRelR of -1.8%.
• Tumor volumes remained stable or slightly decreased in long-term follow-up patients; no correlation with WHO grade was observed.

Conclusions:

• [(11)C]-L-methionine PET is a valuable tool for predicting patient suitability for long-term IFN-alpha therapy and for dose optimization.
• IFN-alpha demonstrated oncostatic effects in patients treated for extended periods (9 months to 8 years).
• Further evaluation in larger patient cohorts is needed to confirm the clinical utility of IFN-alpha, considering potential adverse reactions.