Meningioma Management and Surveillance

Introduction to Meningioma

Meningiomas are classified according to the WHO grading system, which includes WHO grade 1: Benign meningioma, WHO grade 2: Atypical meningioma, and WHO grade 3: Malignant (anaplastic) meningioma 1
The median growth rate for untreated meningiomas is approximately 4 mm per year 1

Diagnostic evaluation should include brain MRI as the standard imaging technique, and SSTR PET imaging when tumor extension is unclear or to differentiate recurrence from treatment-related changes 2
A brain MRI should be obtained within 2 weeks prior to any treatment to establish a baseline for monitoring, as suggested by the European Journal of Nuclear Medicine and Molecular Imaging 2
Consideration of MR spectroscopy, MR perfusion, or PET to rule out radiation-induced necrosis or "pseudoprogression" when misinterpreting post-radiation changes as recurrence 3

The National Comprehensive Cancer Network recommends that treatment of meningiomas should be based on tumor size, location, symptoms, and WHO grade, with observation being preferred for small asymptomatic tumors and surgery being the primary treatment option for symptomatic or large tumors 1
For asymptomatic meningiomas, observation is preferred, but surgery may be considered if the tumor is accessible and potential neurologic consequences exist, followed by radiation therapy (RT) if the tumor is WHO grade 3 1
For symptomatic meningiomas, surgery is the primary treatment option, followed by RT if the tumor is WHO grade 3, or RT alone if surgery is not feasible 1
Radiation therapy can be delivered as fractionated conformal radiotherapy, with doses ranging from 45-54 Gy for WHO grade 1 and 2 meningiomas, and 54-60 Gy for WHO grade 3 meningiomas 1
Stereotactic radiosurgery (SRS) may be considered for small WHO grade 1 meningiomas, with a single fraction dose of 12-15 Gy 1
Peptide Receptor Radionuclide Therapy (PRRT) may be considered for SSTR-positive meningiomas that are no longer responsive to other local therapy options, using [177Lu]Lutetium or [90Y]Yttrium as β-emitters 2
Systemic therapy options, such as hydroxyurea, may be considered for recurrent meningiomas, although clinical trials should be considered when available 1
Alternating electric field therapy may be considered for recurring meningioma in select cases, as a category 2B option 3

The National Comprehensive Cancer Network recommends a structured approach to recurrence management based on tumor characteristics, including WHO grade of original tumor, location and accessibility of recurrence, size of recurrent tumor, patient's overall health status, previous treatments, and tumor growth rate 4
For small (< 3 cm) recurrent tumors, Stereotactic Radiosurgery (SRS) is an option, with a single fraction dose of 12-15 Gy for WHO grade 1 tumors, according to the Journal of the National Comprehensive Cancer Network 4
The National Comprehensive Cancer Network recommends surgical resection for local recurrence where complete resection is possible, and considers placement of carmustine wafers in the surgical bed during reoperation 3
The National Comprehensive Cancer Network suggests reirradiation if prior radiation produced a good or durable response 3
Early detection and treatment of recurrence is warranted as multiple treatment options exist, to avoid delaying treatment for recurrence 3

The American College of Radiology recommends regular MRI imaging for patients with a history of meningioma surgery, with frequency determined by WHO grade, resection status, and time since surgery 4
After treatment for recurrence, surveillance should be resumed with more frequent imaging (every 2-3 months), with gradual extension of intervals if stable, as recommended by unspecified guidelines 4
Post-radiation assessment should include serial MRI scans every 2-4 months for 2-3 years, then less frequently, and consideration of SSTR PET for response assessment after treatment 2
The use of SSTR PET can help differentiate recurrence from treatment-related changes, according to unspecified guidelines 4
MRI may appear worse during the first 3 months after radiation due to BBB dysfunction, not necessarily indicating progression 3

Misinterpreting post-radiation changes as recurrence within the first 3 months after treatment 1, 3
Overlooking SSTR PET for diagnosis and treatment planning, which provides superior detection sensitivity compared to MRI alone 2
Delaying treatment for recurrence when multiple treatment options exist 2, 3
Failing to consider PRRT for appropriate candidates with treatment-refractory meningioma 2