What are the treatment options for a patient diagnosed with meningioma?

Treatment Options for Meningioma

Surgical resection is the primary treatment for symptomatic meningiomas, with complete removal including the dural attachment (Simpson Grade I resection) offering the best chance for cure, while radiotherapy serves as definitive treatment for unresectable tumors or adjuvant therapy for incomplete resections and higher-grade tumors. 1

Initial Management Algorithm

For Newly Diagnosed Meningiomas

Observation is appropriate for:

• Asymptomatic, incidentally discovered small meningiomas (<30 mm) 2
• Elderly patients where surgical risks outweigh benefits 3
• WHO grade 1 tumors without mass effect 2

Surgical resection is indicated for:

• Symptomatic meningiomas causing neurological deficits 1
• Growing tumors on serial imaging 4
• Tumors with significant mass effect 4
• When complete resection including dural attachment is technically feasible 2, 4

Key surgical principle: Complete resection including removal of the dural attachment achieves Simpson Grade I resection in 83-100% of cases in experienced centers, which minimizes recurrence risk 2. Incomplete dural resection significantly increases recurrence rates 2.

Radiotherapy Options

Stereotactic Radiosurgery (SRS)

Best for:

• Residual or recurrent meningiomas <3 cm in diameter 2, 4, 5
• Tumors in surgically inaccessible locations 6
• Medically inoperable patients 6
• SRS achieves higher tumor shrinkage rates (53%) compared to fractionated radiotherapy (29%) 7

Fractionated Stereotactic Radiotherapy (SRT)

Preferred for:

• Larger meningiomas (>3-4 cm) 4, 7
• Tumors near critical structures 7
• Tumors with pre-existing edema 4

External Beam Radiation Therapy (EBRT)

Mandatory for:

• WHO grade 3 (malignant) meningiomas after surgery 2, 4, 5
• Subtotally resected WHO grade 2 (atypical) meningiomas 2, 4, 5

Improves outcomes: Adjuvant radiotherapy for incompletely resected benign meningiomas improves progression-free survival from approximately 50% to over 80% 2

Advanced/Investigational Therapies

Peptide Receptor Radionuclide Therapy (PRRT)

PRRT should be considered only after exhaustion of surgical and radiotherapy options 1. This represents the most promising investigational treatment for refractory meningiomas 1.

Eligibility criteria for PRRT:

• Positive somatostatin receptor type 2 (SSTR2) expression on SSTR-directed PET imaging within 2 months 1, 7
• Karnofsky performance status >60% or ECOG 0-2 7
• Adequate renal function (GFR ≥40 ml/min/1.73 m²) 1, 7
• Adequate bone marrow function (WBC >3,000/μl with ANC >1,000/μl, platelets >75,000/μl, RBC >3,000/μl) 1, 7
• Adequate hepatic function (total bilirubin <3× upper limit normal, albumin >30 g/L, INR <1.5) 1

Relative contraindications:

• Meningioma with mass effect on brainstem (edema risk must be discussed in multidisciplinary board) 1
• Pregnancy 1

Critical caveat: PRRT remains investigational and should ideally be offered within clinical trials or after multidisciplinary assessment 1. Small uncontrolled studies show potential clinical benefit in heavily pretreated patients 1.

Molecular-Targeted Therapies

No molecular target has reached ESCAT I ("ready for clinical use") classification 1. Only two targets reached ESCAT II ("investigational") level:

• mTOR pathway activation 1
• NF2 alterations 1

Molecular testing is NOT recommended at initial diagnosis but should be considered at recurrence when systemic therapy is contemplated 1. Testing should be performed on the most recent tumor tissue sample 1.

Diagnostic Imaging Strategy

MRI Protocol

• MRI with contrast is the gold standard for diagnosis and surveillance 2, 4
• Typical findings: homogeneous dural-based enhancement with dural tail sign 2, 4
• T1-weighted pre- and post-contrast, FLAIR, and T2-weighted sequences required 1

SSTR-Directed PET Imaging

SSTR PET should be obtained when:

• Tumor extension is unclear 1, 2, 4, 7
• Differentiating recurrence from post-treatment changes 1, 2, 4, 7
• Assessing eligibility for PRRT 1, 7
• Detecting multifocal disease or extracranial metastases 1

SSTR PET offers high sensitivity and specificity and is now included in NCCN guidelines for meningioma diagnostic work-up 1.

Surveillance Protocol

Follow-up Imaging Schedule

• WHO grade 1 meningiomas: MRI every 6-12 months 2, 7
• WHO grade 2/3 or recurrent meningiomas: MRI every 3-6 months 7
• After SRS/radiotherapy: Imaging at 1 month, then every 2-3 months for first year 7
• After achieving stable disease (5-10 years): Follow-up intervals can be extended 4

Critical warning: Up to 20% of completely resected benign meningiomas recur within 25 years, necessitating lifelong follow-up 2.

Common Pitfalls to Avoid

• Not all enhancing dural-based lesions are meningiomas: Brain metastases, gliomas, and primary CNS lymphoma can mimic meningiomas radiologically 2
• Incomplete dural resection dramatically increases recurrence risk: The dural attachment must be completely excised when feasible 2
• Failing to obtain SSTR PET when recurrence is suspected: This imaging modality is superior to MRI alone for distinguishing tumor recurrence from treatment-related changes 1, 2, 4, 7
• Considering systemic therapy before exhausting local options: Surgery and radiotherapy should always be prioritized over experimental systemic treatments 1