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 symptomatic meningiomas when feasible, while asymptomatic small tumors (<30 mm) should be observed with serial MRI surveillance. 1, 2

Diagnostic Workup

MRI with contrast is the gold standard imaging modality, revealing characteristic features including homogeneous dural-based enhancement, dural tail sign, and CSF cleft between tumor and brain. 1, 2

• CT scan should be obtained for calcified meningiomas as it better visualizes calcifications that may not be clearly seen on MRI. 1
• SSTR PET imaging should be obtained when tumor extension is unclear or for differentiating recurrence from post-treatment changes, as it provides superior detection sensitivity compared to MRI alone. 3, 2
• The National Comprehensive Cancer Network (NCCN) now includes SSTR-directed PET imaging in diagnostic work-up recommendations for meningiomas. 3

Treatment Algorithm by Clinical Presentation

Asymptomatic Small Meningiomas (<30 mm)

Observation with serial MRI is the recommended approach. 2

• MRI without and with contrast should be performed every 6-12 months. 1, 2
• After achieving stable disease status (typically 5-10 years), follow-up intervals can be extended. 1
• Surgery should be considered only if the tumor is accessible and potential neurological consequences exist. 2

Symptomatic Meningiomas (Any Size)

Surgery is the treatment of choice if accessible. 2

• Complete resection including dural attachment achieves optimal outcomes, with complete resection rates of 55-79% reported in pediatric series and 62% in mixed populations. 3
• Modern image-guided surgery (frameless stereotaxy) improves precision and may reduce surgical side effects. 1, 2
• For skull base meningiomas, specialized neurosurgical expertise is required. 1

Post-Surgical Management Based on WHO Grade

WHO Grade 1 (Benign):

• Observation if complete resection achieved. 1, 2
• Up to 20% may recur within 25 years, necessitating lifelong follow-up. 3, 2

WHO Grade 2 (Atypical):

• External beam radiation therapy (EBRT) is indicated for subtotally resected tumors. 1, 2
• Conventionally fractionated RT to at least 59.4 Gy is considered standard of care. 4
• Stereotactic radiosurgery/hypofractionated stereotactic RT may be considered for small residual tumors after careful discussion, though more studies are needed. 4

WHO Grade 3 (Malignant):

• EBRT is indicated after surgery. 1, 2

Radiation Therapy Options

Stereotactic Radiosurgery (SRS)

SRS is effective for residual or recurrent meningiomas, particularly those <3 cm in diameter. 1, 5

• For cavernous sinus meningiomas, SRS demonstrates 5-year progression-free survival rates of 86-99% and 10-year rates of 69-97%. 1
• Primary SRS/SRT should be considered for small tumors (<3 cm) in critical locations such as cavernous sinus. 1

Hypofractionated Stereotactic Radiotherapy (SRT)

For larger meningiomas or those with pre-existing edema, SRT may have less likelihood of causing post-radiosurgical edema than single-fraction SRS. 1, 5

Advanced Treatment for Refractory Disease

Peptide Receptor Radionuclide Therapy (PRRT)

PRRT using radiolabeled somatostatin receptor ligands shows promising results for treatment-refractory meningiomas, though it is not yet FDA or EMA approved. 3, 2

• SSTR PET imaging must be performed within 2 months prior to PRRT to confirm target expression. 3
• Karnofsky performance status above 60% or ECOG 0-2 is required. 3
• Initial studies present encouraging results with favorable outcomes in patients with treatment-refractory disease. 3
• The most widely used radionuclides are [177Lu]Lutetium and [90Y]Yttrium, both β-emitters. 3

Special Surgical Considerations

Blood loss can be significant during surgery for large or calcified meningiomas, particularly in patients with smaller blood volumes. 1, 5

• Preoperative angiography and possible embolization should be considered for extremely large tumors to minimize blood loss. 1
• Post-operative swelling should be managed with high-dose steroids, head elevation, and close neurological monitoring. 1, 5
• For intraventricular tumors, surgery carries risk of significant blood loss and perioperative mortality. 3

Common Pitfalls

Do not assume all dural-based enhancing lesions are meningiomas - marked T2-hypo- or hyperintensity, absence of dural tail, and dural displacement sign should alert to possible mimics. 2

SSTR PET uptake is not specific for meningiomas - active inflammatory lesions (granulomatous inflammation, neurosarcoidosis), brain metastases, gliomas, and primary CNS lymphoma can show increased uptake, though typically with lower intensity. 3

Rare meningiomas may present with low uptake on SSTR PET (SUV <2.3 or SUVRSSS <3), though this excludes meningioma with high probability. 3

Increasing SSTR tracer uptake during therapy does not necessarily signify failure, whereas diminishing uptake may indicate positive response. 3