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06 Meningioma
Revised: Feb. 2004
Presence of meningioma infrequently may be an accidental radiologic finding on CT scan or MRI booked for various reasons. Where the disease is asymptomatic less than two cm in size and not associated with edema and particularly in patients who are more than 60 years old, observation may be a reasonable approach with annual clinical examination and CT scan. A majority of the other patients and patients who demonstrated radiologic and clinical progression of the tumour are treated surgically. Total excision is usually achieved in tumours located in the convexity dura, falx, lateral aspects of sphenoid wings, frontal base and cerebellar convexity. If pathology demonstrates classic meningioma after total excision, no further treatment is indicated and the patient should be continued on observation with yearly examination and CT scan. Local recurrence rate, however, varies from 8% to 20% over 10 years (1), and patient may require further re-excision with consideration of radiotherapy.
In other locations, gross total excision may not be possible (sagittal sinus, cerebellopontine angle, clivus, cerebral ventricles, tentorial notch, optic nerve sheath). Local recurrence rate for partially excised meningioma varies from 29% to 55% over 10 years (1), and postoperative radiotherapy always should be considered (it is available in the form of conventional/conformal or stereotactic radiotherapy). Local control rate after postoperative radiotherapy for meningioma is 87% over 15 years (2,3,4).
In case pathology demonstrated aggressive meningioma (with one or more of the following features: mitotic activity, pleomorphism, necrosis, high nuclear to cytoplasmic ratio, loss of normal architecture, invasion of surrounding brain), postoperative radiotherapy should always be considered. Local control rate drops down to 54% for aggressive meningiomas (2,3,4).
Malignant meningioma (12% of meningiomas) should be treated aggressively with surgery and postoperative radiotherapy. Investigations, apart from assessment of primary site, should include CXR and bone scan to rule out lung and bony metastasis. Prognosis for this group of patients is poor and five year specific survival is only 34%(5).
Unresectable recurrent meningiomas may occasionally respond to anti-progesterone agents and/or hydroxyurea. These forms of therapy mainly should be considered on clinical trial basis.
References:
- Mirimanoff R.O, et al: Meningioma: Analysis of Recurrence and Progression Following Neurosurgical Resection. J. Neurosurgery 62:18-24. 1985.
- Glaholm J, Bloom H.J.G: The Role of Radiotherapy in the Management of Intracranial Meningiomas: The Royal Marsden Hospital Experience with 186 Patients. I.J.R.O.B.P. 18(9):755-761. 1990.
- Condra K.S, et al: Benign Meningiomas: Primary Treatment Selection Affects Survival. I.J.R.O.B.P. 39(2):427-436. 1997.
- Maire J.P, et al: Fractionated Radiation Therapy in the Treatment of Intracranial Meningiomas: Local Control, Functional Efficacy and Tolerance in 91 Patients. J.J.R.O.B.P. 33(2):315-321. 1995.
- Milosevic M.F, et al: Radiotherapy for Atypical or Malignant Intracranial Meningiomas. I.J.R.O.B.P. 34(4):817-822. 1996.
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