What is the treatment approach for meningioma?

Treatment Approach for Meningioma

Complete surgical resection with removal of the dural attachment is the optimal treatment for most symptomatic meningiomas when feasible, while asymptomatic small lesions (<30 mm) should be observed with serial MRI surveillance. 1

Diagnostic Workup

MRI with contrast is the gold standard imaging modality, demonstrating characteristic homogeneous dural-based enhancement, dural tail sign, and CSF cleft between tumor and brain. 1

• Consider somatostatin receptor (SSTR) PET imaging when tumor extension is unclear on MRI or when differentiating recurrence from post-treatment changes, as SSTR PET provides superior detection sensitivity with excellent lesion-to-background contrast. 2, 1
• SSTR PET is particularly valuable for skull base meningiomas where morphologic borders are difficult to assess on MRI alone. 2
• CT scan provides complementary information for visualizing calcifications and bony involvement. 3

Treatment Algorithm Based on Size and Symptoms

Asymptomatic Small Meningiomas (<30 mm)

Observation with serial MRI every 6-12 months is recommended, as most demonstrate indolent behavior and do not require intervention. 1, 4, 5

• Surgery should be considered if the tumor is accessible and potential neurological consequences exist. 1
• Observation is particularly appropriate for elderly patients, those with significant comorbidities, or tumors in eloquent/deep locations. 1, 4

Symptomatic Meningiomas or Growing Lesions

Surgery is the treatment of choice when accessible, with the goal of complete resection including dural attachment. 1, 6

• Modern image-guided surgery (frameless stereotaxy) improves precision and reduces surgical complications. 1
• For skull base or intraventricular meningiomas, specialized neurosurgical expertise is required due to higher surgical risks. 1, 7

Radiation Therapy Indications

External beam radiation therapy (EBRT) is indicated for WHO grade 3 (malignant) meningiomas after surgery and for subtotally resected WHO grade 2 (atypical) meningiomas. 1, 3

Stereotactic Radiosurgery (SRS)

SRS is effective for residual or recurrent meningiomas, particularly those <3 cm in diameter, with 5-year progression-free survival rates of 86-99%. 2, 3

• For cavernous sinus meningiomas, SRS and stereotactic radiotherapy (SRT) confer favorable benefit-to-risk profiles with neurological preservation rates of 80-100%. 2
• For larger meningiomas (>3 cm) or those with pre-existing edema, hypofractionated SRT is preferred over single-fraction SRS to minimize risk of post-treatment edema. 2, 3
• SRS offers higher tumor shrinkage rates (53%) compared to SRT (29%), though clinical improvement is similar. 2

Advanced Treatment: Peptide Receptor Radionuclide Therapy (PRRT)

PRRT using [177Lu]Lutetium or [90Y]Yttrium-labeled somatostatin analogs shows promising results for treatment-refractory meningiomas, though randomized trials are lacking and it is not yet FDA-approved. 2, 1

Eligibility Criteria for PRRT

• Positive SSTR expression on PET imaging within 2 months. 2
• Karnofsky performance status >60% or ECOG 0-2. 2
• Baseline brain MRI within 2 weeks prior to treatment. 2

• 25% reduction in SSTR PET uptake may indicate positive response to therapy. 2

Post-Treatment Surveillance

MRI without and with contrast every 6-12 months is recommended for WHO grade 1 meningiomas, with intervals potentially extended after achieving stable disease (typically 5-10 years). 1, 3

• SSTR PET has high accuracy in differentiating recurrent tumor from post-treatment scar tissue or radionecrosis. 2
• The post-radiotherapy MRI should serve as the new baseline rather than the post-surgical MRI. 1

Critical Pitfalls to Avoid

Not all enhancing dural-based lesions are meningiomas—brain metastases, gliomas, and primary CNS lymphoma can mimic meningiomas on imaging. 2, 7

• Rare meningioma cases may show low or absent uptake on SSTR PET (SUV <2.3), though this has high negative predictive value. 2
• Inflammatory lesions (granulomatous inflammation, neurosarcoidosis) may show increased SSTR uptake. 2
• Underestimating blood loss risk during surgery, particularly for intraventricular meningiomas, can lead to inadequate preparation. 3, 7
• Failing to obtain specialized surgical expertise for complex locations (skull base, intraventricular) increases morbidity risk. 1, 7

Special Populations

Malignant Meningiomas (WHO Grade 2-3)

Maximal safe surgical resection followed by focal radiation is standard initial therapy, though prognosis remains poor with high recurrence rates. 8

• The role of chemotherapy at recurrence is unclear, though hydroxyurea has shown modest success in limited data. 6, 8

Elderly or High-Risk Patients

Stereotactic radiotherapy may be preferred over surgery for patients with significant comorbidities or meningiomas in eloquent/surgically inaccessible locations. 6