Fractionated stereotactic radiosurgery for the treatment of meningiomas
Although the vast majority of meningiomas are not malignant, their location within the cranial vault often leads to the development of symptoms. Traditional therapy has included observation, surgical resection, radiation therapy or a multimodality approach. The objective of this study is to review the outcomes in patients with meningioma treated at our institution using stereotactic radiosurgery.
A total of 73 patients (median age of 59, 15 male and 58 female) with meningioma (median volume of 5.54 cc) underwent Cyber Knife TM stereotactic radiosurgery at our institution. Sixty patients had WHO grade 1 meningioma, eleven patients had WHO grade 2 meningioma, and two patients had WHO grade 3 meningioma. Treatment consisted of a median dose of 17.5 Gy (range, 6 - 27 Gy) delivered over a median of three fractions (range: 1 - 5). The patients were followed by clinical examination as well as serial imaging with magnetic resonance imaging (MRI).
The median follow-up was 16.1 months (range, 1.5 - 98.0). Follow-up MRI was available in all 73 patients. Local failure was documented in 11 cases. Actuarial local control at one year was 95, 71, and 0% for WHO grade 1, WHO grade 2, and WHO grade 3, respectively. There was no acute grade 3 or greater toxicity and only one episode of late grade 3 toxicity. A subjective improvement in the existing, tumor-related symptoms was noted in 60% of the patients.
Stereotactic radiosurgery is a safe and effective treatment for meningioma. Tumor-related symptoms often improve after treatment.
Available from: Anat O Stemmer-Rachamimov
- "Meningiomas are the most common type of brain tumor, accounting for 34% of all central nervous system tumors. Despite the high prevalence of meningiomas in the general population, there are currently no medical treatments available.,  For sporadic meningiomas that require active treatment, surgery and radiation therapy are usually effective. "
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ABSTRACT: Bevacizumab treatment can result in tumor shrinkage of progressive vestibular schwannomas in some neurofibromatosis 2 (NF2) patients but its effect on meningiomas has not been defined.
To determine the clinical activity of bevacizumab against NF2-related meningiomas, we measured changes in volume of meningiomas in NF2 patients who received bevacizumab for treatment of progressive vestibular schwannomas. A radiographic response was defined as a 20% decrease in tumor size by volumetric MRI analysis. In addition, we determined the expression pattern of growth factors associated with tumor angiogenesis in paraffin-embedded tissues from 26 unrelated meningiomas. A total of 48 meningiomas in 15 NF2 patients were included in this study with a median follow up time of 18 months. A volumetric radiographic response was seen in 29% of the meningiomas (14/48). Tumor shrinkage was not durable: the median duration of response was 3.7 months and the median time to progression was 15 months. There was no significant correlation between pre-treatment growth rate and meningioma response in regression models. Tissue analysis showed no correlation between tumor microvascular density and expression of VEGF pathway components. This data suggests that, in contrast to schwannomas, activation of VEGF pathway is not the primary driver of angiogenesis in meningiomas. Our results suggest that a minority of NF2-associated meningiomas shrink during bevacizumab therapy and that these responses were of short duration. These results are comparable to previous studies of bevacizumab in sporadic meningiomas.
Available from: Dafydd Gareth Evans
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ABSTRACT: Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome characterized by bilateral vestibular schwannomas (VS) which often result in deafness despite aggressive management. Meningiomas, ependymomas, and other cranial nerve and peripheral schwannomas are also commonly found in NF2 and collectively lead to major neurologic morbidity and mortality. Traditionally, the overall survival rate in patients with NF2 is estimated to be 38% at 20 years from diagnosis. Hence, there is a desperate need for new, effective therapies. Recent progress in understanding the molecular basis of NF2 related tumors has aided in the identification of potential therapeutic targets and emerging clinical therapies. In June 2010, representatives of the international NF2 research and clinical community convened under the leadership of Drs. D. Gareth Evans (University of Manchester) and Marco Giovannini (House Research Institute) to review the state of NF2 treatment and clinical trials. This manuscript summarizes the expert opinions about current treatments for NF2 associated tumors and recommendations for advancing therapies emerging from that meeting. The development of effective therapies for NF2 associated tumors has the potential for significant clinical advancement not only for patients with NF2 but for thousands of neuro-oncology patients afflicted with these tumors. © 2011 Wiley Periodicals, Inc.
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To find out whether the use of stereotactic techniques for fractionated radiotherapy reduces toxicity to the endocrine and visual system in patients with benign perioptic tumors.
Patients and methods:
From 1993 to 2009, 29 patients were treated with fractionated stereotactic radiotherapy. The most frequent tumor types were grade I meningioma (n = 11) and pituitary adenoma (n = 10, 7 nonfunctioning, 3 growth hormone-producing). Patients were immobilized with the GTC frame (Radionics, USA) and the planning target volume (PTV; median 24.7, 4.6-58.6 ml) was irradiated with a total dose of 52.2 Gy (range, 45.0-55.8 Gy) in 1.8-Gy fractions using a linear accelerator (6 MeV photons) equipped with a micro-multileaf collimator. Maximum doses to the optic system and pituitary gland were 53.4 Gy (range, 11.5-57.6 Gy) and 53.6 Gy (range, 12.0-57.9 Gy).
Median follow-up was 45 months (range, 10-105 months). Local control was achieved in all but 1 patient (actuarial rate 92% at 5 years and 10 years). In 9 of 29 patients (31%), partial remission was observed (actuarial response rate 40% at 5 years and 10 years). In 4 of 26 patients (15%) with at least partial pituitary function, new hormonal deficits developed (actuarial rate 21% at 5 years and 10 years). This rate was significantly higher in patients treated for a larger PTV (< /> 25 ml: 0% vs. 42% at 5 years and 10 years, p = 0.028). Visual function improved in 4 of 15 patients (27%) who had prior impairment. None of the patients developed treatment-related optic neuropathy, but 2 patients experienced new disease-related visual deficits.
Fractionated stereotactic radiotherapy for benign tumors of the perioptic and sellar region results in satisfactory response and local control rates and does not affect the visual system. The assumption that patients can be spared hypophyseal insufficiency only holds for small tumors.
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