Majority (~2/3) of asymptomatic, incidentally found meningiomas are stable on imaging. If they progress, the rate of growth tends to be 2-4 mm per year and tumor doubling time is on average 20 years
Calcified and hypointense on T2 meningiomas appear less likely to progress; elderly patients appear to have slower growth rates
Reasonable to consider observation for asymptomatic meningiomas, particularly in elderly patients or patients with skull-base (high operative risk) tumors. If so, MRI at 3 months, then 6 months later, then annually is considered reasonable
For younger patients and patients with non-calcified tumors, consider treatment due to higher expected growth rates
Tel Aviv; 2004 (Israel)(1989-1999) PMID 15452322 -- "Natural history of conservatively treated meningiomas." (Herscovici Z, Neurology. 2004 Sep 28;63(6):1133-4.)
Retrospective. 43 patients, 51 meningiomas
Outcome: 63% no growth, 37% growth (mean growth rate 4 mm / year)
Predictors: younger age, sphenoid ridge location, non calcified, hyperintense on MRI T2 predicted for growth
Hannover; 2003PMID 12823874 -- "The natural history of incidental meningiomas." (Nakamura M, Neurosurgery. 2003 Jul;53(1):62-70; discussion 70-1.)
Outcome: volumetric growth mean 0.8 cm3 / year, 66% growth rates <1 cm3 / year; tumor doubling mean 22 years (1.3 - 143 years). Higher growth rates in younger patients. No correlation between initial size and doubling time. Less likely to progress if calcified
Conclusion: Majority of incidental meningiomas minimal growth; can be managed conservatively
Mayo; 1998PMID 9855530 -- "The natural history of asymptomatic meningiomas in Olmsted County, Minnesota." (Go RS, Neurology. 1998 Dec;51(6):1718-20.)
Retrospective. 35 asymptomatic patients found incidentally. Mean F/U 6.2 years
Outcome: 88% stable, 12% progressed, 3% (1 patient) developed symptoms. Less likely to progress if calcified
Northwestern; 1997PMID 9153494 -- "Meningiomas: the decision not to operate." (Braunstein JB, Neurology. 1997 May;48(5):1459-62.)
Retrospective. 12 patients managed conservatively in 100 consecutive meningiomas, either with no symptoms or high operative risk. Mean F/U 8.8 years
Outcome: growth in 1/12 patients
Illinois; 1995PMID 7616265 -- "The natural history and growth rate of asymptomatic meningiomas: a review of 60 patients." (Olivero WC, J Neurosurg. 1995 Aug;83(2):222-4.)
Retrospective. 60 patients diagnosed with asymptomatic meningioma. 45 patietns follow up scans at 3 months, 9 months, then q 1 year. Average F/U 2.7 years (0.5-15).
Outcome: 67% no growth (average F/U 2.4 years, max 6 years); 22% tumor growth (2.4 mm per year, range 2 mm - 1 cm)
Conclusion: Need for close follow-up to rule out rapidly enlarging tumors
Frequently considered for symptomatic patients, younger patients, and patients with expanding/infiltrating tumors
Complications: range 2-30% depending on location and type
Mortality: range 1-14%; worse in elderly
Resectability plays an important role:
Completeness of resection - Simpson GradePMID 13406590 - predicts for likelihood of local recurrence
Gross total resection (Grade I-III) in ~80%, leading to 10-year PFS of ~80%
Subtotal resection typically in cavernous sinus, petroclival region, posterior superior sagittal sinus, and optic nerve sheath tumors; have 4.2x relative excess death risk compared to complete resection
Completeness of Resection
complete removal including resection of underlying bone and associated dura
complete removal + coagulation of dural attachment
complete removal w/o resection of dura or coagulation
Grade is also important: 15-year OS benign 80% vs. atypical/anaplastic 51%, risk of death 4.6x
Helsinki; 1992 (Finland)(1953-1980) PMID 1641106 -- "Factors affecting operative and excess long-term mortality in 935 patients with intracranial meningioma." (Kallio M, Neurosurgery. 1992 Jul;31(1):2-12.)
Retrospective. 935 patients treated with surgery.
Outcome: 1-year DSS 91%, 15-year DSS 78%; subtotal resection 4.2x risk of death; malignant histology 4.6x risk of death
Germany (1985-2009) -- Atypical and malignant meningiomas
62 pts w/ atypical and 23 pts w/ malignant meningiomas, s/p RT (60% after surgical resection, 19% at disease progression, 8% as primary treatment). Average dose 57.6 Gy in 1.8-3 Gy fx.
2012PMID 22137023 -- "Long-term outcome after radiotherapy in patients with atypical and malignant meningiomas--clinical results in 85 patients treated in a single institution leading to optimized guidelines for early radiation therapy." (Adeberg S, Int J Radiat Oncol Biol Phys. 2012 Jul 1;83(3):859-64.)
5-yr OS: 81% atypical and 53% malignant. PFS: 95% and 50% (at 2 and 5 yrs) for atypical, and 63% and 13% for malignant.
Conclusion: "RT resulted in improvement of preexisting clinical symptoms; outcome is comparable to other series reported in the literature."
France (1999-2006) -- Atypical and malignant meningiomas
19 pts w/ atypical and 5 pts w/ malignant meningiomas, s/p RT. Treatment at Centre de Protontherapie d'Orsay (CPO). Median total RT dose 68 CGE (34 Gy photons + 34 CGE protons).
2009PMID 19203844 -- "Combined proton and photon conformal radiotherapy for intracranial atypical and malignant meningioma." (Boskos C, Int J Radiat Oncol Biol Phys. 2009 Oct 1;75(2):399-406.)
Survival associated with dose > 60 Gy.
Conclusion: "Postoperative combination of conformal radiotherapy with protons and photons for atypical and malignant meningiomas is a well-tolerated treatment producing long-term tumor stabilization."
UC San Francisco
Atypical meningiomas; 2009 (1993-2004) PMID 19145156 -- "Long-term recurrence rates of atypical meningiomas after gross total resection with or without postoperative adjuvant radiation." (Aghi MK, Neurosurgery. 2009 Jan;64(1):56-60; discussion 60.)
Retrospective. 108 atypical meningioma, gross total resection. Adjuvant radiation in 8 patients.
Outcome: recurrence rate 28%, mean time to recurrence 3 years. No recurrence with the 8 patients who received adjuvant RT. Patients with recurrences underwent RT, and average 2.7 craniotomies/patient. Tumor-related mortality after recurrence 30%
Conclusion: High recurrence rate for atypical meningiomas after GTR without adjuvant radiation; causing numerous reoperations and shortened survival
Subtotal resection; 1994 (1967-90) PMID 8283256 -- "Postoperative irradiation for subtotally resected meningiomas. A retrospective analysis of 140 patients treated from 1967 to 1990," (Goldsmith BJ, J Neurosurg. 1994 Feb;80(2):195-201.)
Retrospective. 140 pts (117 benign, 23 malignant) treated with adjuvant RT. RT median dose 54 Gy, benign margin 1-2cm, malignant margin 1-3cm. Median FU 3.3 years
Outcome: 5-year OS benign 85% vs. malignant 58% (SS); 10-year benign PFS and OS 77% (no 10 year outcomes for malignant)
Local control at 10 yrs: STR alone (18%), STR + xrt (82%), GRT (77%)
Princess Margaret (1966-90) PMID 8598358 -- Milosevic MF et al. "Radiotherapy for atypical or malignant intracranial meningioma," Int J Radiat Oncol Biol Phys. 1996 Mar 1;34(4):817-22.
59 pts w/ atypical or malignant meningioma. 17 had GTR, 35 had STR, others had bx or other. All pts received xrt (median dose 50 Gy).
5yr OS was 28%, 5yr CSS was 34%
Age < 58, xrt dose > 50 Gy were independent predictors of higher CSS on multivariate analysis.
Cleveland Clinic (1979-95) PMID 10656373 -- Goyal LK et al. "Local control and overall survival in atypical meningioma: a retrospective study," Int J Radiat Oncol Biol Phys. 2000 Jan 1;46(1):57-61.
22 atypical meningioma, 8 received xrt in the range of 54 Gy (35-59.4), 15 had GTR
Pts w/ GTR had 5 and 10 yr OS of 87% and 87%; Pts w/ STR had 5 and 10 yr OS of 100% and 75%
MGH (1981-96) PMID 11121635 -- Wenkel E et al. "Benign meningioma: partially resected, biopsied, and recurrent intracranial tumors treated with combined proton and photon radiotherapy," Int J Radiat Oncol Biol Phys. 2000 Dec 1;48(5):1363-70.
46 pts w/ subtotally resected, bx'd, or recurrent meningioma tx'd w/ combined photon/proton xrt (9 w/ STR, 8 w/ bx only, 29 w/ recurrence after surg). Median dose 59 CGE.
5 yr OS was 93% and 10 yr OS was 77%
8 pts had severe long term toxicity and 1 pt died of brainstem necrosis. Toxicity appeared dose related.
Conclusion: SRS safe and effective, therapeutic window 12-16 Gy to 50% isodose at tumor margin
University of Maryland, 2005 (1992-2000) PMID 15590183 -- DiBiase SJ et al. "Factors predicting local tumor control after gamma knife stereotactic radiosurgery for benign intracranial meningiomas," Int J Radiat Oncol Biol Phys. 2004 Dec 1;60(5):1515-9.
137 pts w/ benign meningioma; 62% tx'd definitively, while remaining had previous resection. Median 14 Gy to 50% isodose.
Prognostic factors associated w/ worse prognosis were conformity index < 1.4, male sex, and size >10 cc.
Mayo Clinic, 2003 (1990-97) PMID 12605979 -- Pollock BE et al. "Stereotactic radiosurgery provides equivalent tumor control to Simpson Grade 1 resection for patients with small- to medium-size meningiomas," Int J Radiat Oncol Biol Phys. 2003 Mar 15;55(4):1000-5.
198 adult meningioma <3.5 cm tx'd w/ either surgery (136) or SRS (62); for SRS, mean margin dose of 17.7 Gy w/ mean max dose of 34.9 Gy.
No statistically significant difference b/w Simpson Grade I resections and SRS tx'd pts in terms of PFS (100% vs 96% respectively).
Retrospective. 15 patients. Median age 52 years. RT for gross residual tumor, 1/3 underwent radiation therapy for tumors that had recurred within 1 year of surgery, minimum f/u 5 years, median 12yrs, Target definition is GTV= Visible tumor on MRI scan, CTV= GTV+5mm along length of ON, PTV= CTV+ 2 to 5mm magin
Outcome: No patient experianced tumor progression, LC/RC/RFF all 100%, vision status after radiation therapy: Stable 60%, Improved in 27%, Decreased 13%, Moderate retinopathy in 2 patients
Conclusion: RT with 50.4Gy at 1.8Gy per treatment prevents tumor growth and vision deterioration
Tubingen; 2006 (1981-2002) (Germany) PMID 16191463 -- "The role of surgery in meningiomas involving the optic nerve sheath." (Roser F, Clin Neurol Neurosurg. 2006 Jul;108(5):470-6.)
Retrospective. 24 patients. Female 7:1 male, mean age 44 years. Surgery pterional craniotomy, intra/extradural subtotal excision, bony decompression
Outcome: Low morbidity, preserved/improved vision in 50% patients. Long-term vision loss due to recurrence in 20%
Conclusion: RT should be primary treatment option as it prolongs time to functional loss; surgery for intracranial extension, disfiguring proptosis, and rapid visual deterioration