What is the initial treatment approach for a patient diagnosed with meningioma?

Initial Treatment Approach for Meningioma

For newly diagnosed meningioma, complete surgical resection including the dural attachment is the optimal initial treatment when the tumor is accessible and the patient is a surgical candidate, as this offers the best chance for cure. 1, 2

Treatment Algorithm Based on Clinical Presentation

Asymptomatic Small Meningiomas (<30 mm)

• Observation with serial MRI surveillance is recommended for asymptomatic small meningiomas, particularly if located in eloquent brain regions, deep structures, or brainstem areas 2
• MRI without and with contrast should be performed every 6-12 months initially 1, 2
• Surgery should be considered if the tumor shows growth on serial imaging or if accessible with low surgical risk 2
• Over 60% of asymptomatic meningiomas will not grow in size, particularly those with calcifications or hypointense regions on T2-weighted MRI 3

Symptomatic Meningiomas (Any Size)

• Proceed directly to surgical resection if accessible 2
• Complete resection with removal of the dural attachment is the goal, as completeness of resection is the single most important prognostic factor for recurrence 4
• Modern image-guided surgery (frameless stereotaxy) should be utilized to improve precision and reduce surgical complications 1, 2

Post-Surgical Management Based on WHO Grade

WHO Grade 1 (Benign - 90% of cases):

• If complete resection achieved: observation with MRI surveillance every 6-12 months 1, 2
• If incomplete resection: consider observation versus adjuvant radiation therapy based on residual tumor size and location 5

WHO Grade 2 (Atypical - 6% of cases):

• After subtotal resection: conventionally fractionated external beam radiation therapy (EBRT) to at least 59.4 Gy is standard of care 6
• After gross total resection: adjuvant radiation therapy should be strongly considered 2, 6
• Larger margins are preferred based on prospective data; stereotactic radiosurgery is less appropriate as primary adjuvant treatment 6

WHO Grade 3 (Malignant - 2% of cases):

• EBRT is indicated after surgery regardless of resection extent 1, 2
• Radiation dose of 54 Gy (1.8 to 2 Gy per fraction) yields results comparable to total resection for incomplete resections 4

Alternative Primary Treatment Options

Stereotactic Radiosurgery (SRS) as Primary Treatment

• Consider SRS for small tumors (<3 cm) in surgically inaccessible or high-risk locations such as cavernous sinus 1
• SRS for cavernous sinus meningiomas demonstrates 5-year progression-free survival of 86-99% and 10-year rates of 69-97% 1
• Appropriate for elderly patients, those with significant comorbidities, or tumors in eloquent locations 5
• Not recommended for asymptomatic meningiomas that are surgically accessible 2

Hypofractionated Stereotactic Radiotherapy (SRT)

• Preferred over single-fraction SRS for larger meningiomas or those with pre-existing edema, as it has less likelihood of causing post-radiosurgical edema 1, 7

Special Considerations

Calcified Meningiomas

• CT scan should be obtained as it better visualizes calcifications not clearly seen on MRI 1, 7
• Blood loss can be significant during surgery; preoperative angiography and possible embolization should be considered for extremely large tumors 1, 7
• Post-operative swelling should be managed with high-dose steroids, head elevation, and close neurological monitoring 1, 7

Molecular Testing Timing

• Molecular testing for targeted therapy selection is not recommended at initial diagnosis but should be considered at recurrence after exhaustion of surgical and radiotherapy options 8
• Testing on the most recent tumor tissue sample is preferred, as molecular alterations may change with tumor progression 8

Advanced/Experimental Options (Not First-Line)

Peptide Receptor Radionuclide Therapy (PRRT)

• PRRT is considered experimental and should only be used after exhaustion of surgical resections and radiotherapy options 8
• Somatostatin receptor (SSTR) PET imaging must be performed prior to PRRT to confirm target expression 8, 2
• Standard regimen consists of 4 treatment cycles of 7.4 GBq [177Lu]-labeled radioligands spaced 8±2 weeks apart 8
• Requires multidisciplinary neuro-oncology board decision and preferably enrollment in clinical trials 8

Systemic Therapy

• Reserved for unresectable tumors or when all other treatments (surgery and radiotherapy) have failed 5
• Hydroxyurea has shown modest success in recurrent meningiomas 5, 4

Critical Pitfalls to Avoid

• Do not delay surgical consultation for incidental meningiomas - neurosurgical evaluation is recommended for all patients even if observation is ultimately chosen 3
• Do not use stereotactic radiosurgery as adjuvant treatment for WHO grade 2 meningiomas after gross total resection - conventionally fractionated RT with larger margins is preferred 6
• Do not assume all meningiomas are benign - approximately 8% are atypical or malignant and require more aggressive treatment 5
• Recurrence can occur up to 20% within 25 years even for completely resected benign meningiomas, necessitating long-term follow-up 2