International Journal of Radiation Oncology*Biology*Physics
Clinical investigationBrainIntensity-Modulated Radiotherapy for Complex-Shaped Meningioma of the Skull Base: Long-Term Experience of a Single Institution
Introduction
Meningiomas are the most common nonglial primary brain tumors, representing approximately 15% of all central nervous system tumors in adults with a predomination in women (1, 2). Using the World Health Organization (WHO) criteria, most meningiomas are histologic benign and slow-growing lesions (3). Treatment of primary choice is complete surgical resection (4, 5). Because of their proximity to critical structures, especially the optical system, cranial nerves and brainstem, and neurovascular system, meningioma may often not be amenable to a safe and complete surgical approach. After subtotal resection, meningioma show a high tendency for local recurrence. Therefore, postoperative radiation therapy is necessary to prevent local tumor recurrence (6, 7). In the literature, 5-year local tumor control rates in patients with benign meningioma reported to range from 89% to 100% after radiosurgery and fractionated stereotactic radiation therapy compared with 85% at 10 years after conventional radiotherapy (8, 9, 10, 11). Intensity-modulated radiation therapy (IMRT) as an advanced form of three-dimensional conformal radiation therapy has been shown to have the ability to conform the dose to concavities and to better avoid organs at risk (12, 13, 14). IMRT allows the modulation of beam intensity to achieve the desired dose distribution for the planning target volume and radiosensitive critical structures by using inverse planning strategies, optimization algorithms, and dose constraints.
The present article is an analysis of our long-term experience with IMRT in the treatment of complex-shaped meningioma, and meningioma that are adherent to, or encompass, critical structures with respect to long-term local tumor control, as well as side effects of irradiation and overall survival of the patients.
Section snippets
Patients and Methods
Between January 1998 and December 2004, 94 patients with a median age of 57.2 years (range, 13.3–79.2 years) were treated with IMRT at the German Cancer Research Center, Heidelberg, Germany. The male/female ratio was 1:3.6 (25:69) patients; median Karnofsky performance score was 90%. Sixty-four patients had a histologic-proven diagnosis of meningioma. In 30 patients, no biopsy was obtained because of the high risk of permanent neurologic deficits, but the clinical and radiologic characteristics
Results
Median follow-up was 4.4 years (range, 1.6–82.7 months). A total of 97% of the patients (91/94 patients) were followed for more than 12 months and 75.5% (71/94 patients) for more than 36 months.
Discussion
As reported in the literature, radiotherapy is capable of improving local tumor control if complete surgical resection of a meningioma is not achievable. Therefore, the indication of radiotherapy treatment is accepted for residual, unresectable meningiomas and in recurrent disease. Especially complex-shaped skull base tumors are a challenge to the radiation oncologist because of their proximity to critical radiosensitive structures. IMRT improves local control in these difficult to treat tumors
Conclusion
These data demonstrate that IMRT is an effective and safe treatment modality for long-term local control of especially complex-shaped and otherwise difficult to treat meningioma of the skull base with lower risk for adverse effects. Furthermore, IMRT offers the possibility of highly conformal irradiation, while sparing adjacent critical radiosensitive structures with the potential of dose escalation for malignant meningiomas.
References (31)
- et al.
The role of radiotherapy in the management of intracranial meningeomasThe Royal Merden Hospital experience with 186 patients
Int J Radiat Oncol Biol Phys
(1990) - et al.
Intensity-modulated radiotherapy (IMRT) for recurrent, residual, or untreated skull-base meningiomas: Preliminary clinical experience
Int J Radiat Oncol Biol Phys
(2003) - et al.
Intensity-modulated stereotactic radiotherapy vs. stereotactic conformal radiotherapy for the treatment of meningioma located predominantly in the skull base
Int J Radiat Oncol Biol Phys
(2003) Comparison of three-dimensional conformal radiation therapy and intensity-modulated radiation therapy systems
Semin Radiat Oncol
(1999)- et al.
Intensity modulation with the “step and shoot” technique using a commercial MLC: A planning study
Int J Radiat Oncol Biol Phys
(1999) - et al.
Intensity-modulated radiosurgery/radiotherapy using a micromultileaf collimator
Int J Radiat Oncol Biol Phys
(2001) - et al.
Intensity-modulated stereotactic radiosurgery using dynamic micro-multileaf collimation
Int J Radiat Oncol Biol Phys
(2001) - et al.
Radiation optic neuropathy after megavoltage external beam irradiation: Analysis of time-dose factors
Int J Radiat Oncol Biol Phys
(1994) - et al.
Stereotactic single high dose radiation therapy of benign intracranial meningiomas
Int J Radiat Oncol Biol Phys
(1990) - et al.
The role of Gamma knife radiosurgery in the management of cavernous sinus meningiomas
Int J Radiat Oncol Biol Phys
(2002)
Etiology and biology of meningeomas
The role of radiation therapy in the treatment of subtotally resected benign meningiomas
J Neuro-Oncol
Meningioma: Analysis of recurrence and progression following neurosurgical resection
J Neurosurg
Meningiomas: Genetics, malignancy, and the role of radiation in induction and treatmentThe Richard C. Schneider Lecture
J Neurosurg
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2019, Interdisciplinary Neurosurgery: Advanced Techniques and Case ManagementFractionated radiotherapy and radiosurgery of intracranial meningiomas
2018, NeurochirurgieCitation Excerpt :The clinical target volume (CTV) is defined according to the natural history of meningiomas. With the availability of high-resolution MRI and image registration (often called erroneously “fusion”) capabilities, CTV margins for grade I meningioma remain limited from 0 to few millimeters [19,41,64]. For SRS, most series do not detail target definition, but the general SRS principle is to target enhancing disease alone (GTV = CTV) [41].
Lessons learned from reirradiation of recurrent skull base meningioma: A case report and review of the literature
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Conflict of interest: none.