Fractionated radiation therapy in the treatment of intracranial meningiomas: local control, functional efficacy, and tolerance in 91 patients

Anaplastic Transformation of Sphenoid Wing Meningioma With Orbital and Cavernous Sinus Invasion: Unveiling the Aggressive Nature

Primary tumors in the central nervous system, known as meningiomas, are frequently found and constitute a substantial proportion of tumor cases. Although generally benign, there are occasional cases where they might exhibit malignant characteristics. Anaplastic meningioma is a rare subtype of malignant meningiomas, representing only a small proportion of cases. We present the case of a 70-year-old female patient who presented to the Neurosurgery Clinic of University Hospital "Saint George" with clinical manifestations of monocular vision and blurry vision in the right eye for three months. On physical examination, unilateral ptosis and mydriasis were noted in the left eye. MRI revealed an extra-axial mass located supratentorial in the left temporopolar region affecting the wing of the left sphenoidal bone, invading the cavernous sinus, suppressing the left and right optic nerves, and involving the left orbit. Operative treatment was performed through a left pterional craniotomy and resection of the tumor mass by microsurgical technique. The subdural, epidural, and intraorbital mass were resected. Total removal of the tumor was not achievable and subtotal resection was performed. Pathology results showed that the tumor mass was anaplastic meningioma. Surgery-related complications were not observed. Postoperatively, the patient was mobilized on the day after intervention and the control CT scan showed no ischemic or hemorrhagic events. The patient experienced relief in her symptoms and was discharged on the fifth day. The patient underwent radiation therapy, resulting in the complete removal of the left tumor in the cavernous sinus. After six months, no tumor recurrence was found, and a long-term follow-up is planned to monitor for possible recurrence.

Management of cavernous sinus meningiomas: Consensus statement on behalf of the EANS skull base section

Introduction

The evolution of cavernous sinus meningiomas (CSMs) might be unpredictable and the efficacy of their treatments is challenging due to their indolent evolution, variations and fluctuations of symptoms, heterogeneity of classifications and lack of randomized controlled trials. Here, a dedicated task force provides a consensus statement on the overall management of CSMs.

Research question

To determine the best overall management of CSMs, depending on their clinical presentation, size, and evolution as well as patient characteristics.

Material and methods

Using the PRISMA 2020 guidelines, we included literature from January 2000 to December 2020. A total of 400 abstracts and 77 titles were kept for full-paper screening.

Results

The task force formulated 8 recommendations (Level C evidence). CSMs should be managed by a highly specialized multidisciplinary team. The initial evaluation of patients includes clinical, ophthalmological, endocrinological and radiological assessment. Treatment of CSM should involve experienced skull-base neurosurgeons or neuro-radiosurgeons, radiation oncologists, radiologists, ophthalmologists, and endocrinologists.

Discussion and conclusion

Radiosurgery is preferred as first-line treatment in small, enclosed, pauci-symptomatic lesions/in elderly patients, while large CSMs not amenable to resection or WHO grade II-III are candidates for radiotherapy. Microsurgery is an option in aggressive/rapidly progressing lesions in young patients presenting with oculomotor/visual/endocrinological impairment. Whenever surgery is offered, open cranial approaches are the current standard. There is limited experience reported about endoscopic endonasal approach for CSMs and the main indication is decompression of the cavernous sinus to improve symptoms. Whenever surgery is indicated, the current trend is to offer decompression followed by radiosurgery.

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A thorough evaluation of cavernous sinus meningiomas by a multidisciplinary team is mandatory.

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Microsurgery should be considered for aggressive lesions in young patients.

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Extended endoscopic approaches can be effective when combined with radiotherapy.

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Stereotaxic radiotherapy and stereotaxic radiosurgery offer excellent tumour control in small/asymptomatic lesions .

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

Fractionated Gamma Knife radiosurgery for skull base meningiomas: a single-institution experience

OBJECTIVEGamma Knife radiosurgery (GKRS) has been successfully used for the treatment of intracranial meningiomas given its steep dose gradients and high-dose conformality. However, treatment of skull base meningiomas (SBMs) may pose significant risk to adjacent radiation-sensitive structures such as the cranial nerves. Fractionated GKRS (fGKRS) may decrease this risk, but until recently it has not been practical with traditional pin-based systems. This study reports the authors' experience in treating SBMs with fGKRS, using a relocatable, noninvasive immobilization system.METHODSThe authors performed a retrospective review of all patients who underwent fGKRS for SBMs between 2013 and 2018 delivered using the Extend relocatable frame system or the Icon system. Patient demographics, pre- and post-GKRS tumor characteristics, perilesional edema, prior treatment details, and clinical symptoms were evaluated. Volumetric analysis of pre-GKRS, post-GKRS, and subsequent follow-up visits was performed.RESULTSTwenty-five patients met inclusion criteria. Nineteen patients were treated with the Icon system, and 6 patients were treated with the Extend system. The mean pre-fGKRS tumor volume was 7.62 cm3 (range 4.57-13.07 cm3). The median margin dose was 25 Gy delivered in 4 (8%) or 5 (92%) fractions. The median follow-up time was 12.4 months (range 4.7-17.4 months). Two patients (9%) experienced new-onset cranial neuropathy at the first follow-up. The mean postoperative tumor volume reduction was 15.9% with 6 patients (27%) experiencing improvement of cranial neuropathy at the first follow-up. Median first follow-up scans were obtained at 3.4 months (range 2.8-4.3 months). Three patients (12%) developed asymptomatic, mild perilesional edema by the first follow-up, which remained stable subsequently.CONCLUSIONSfGKRS with relocatable, noninvasive immobilization systems is well tolerated in patients with SBMs and demonstrated satisfactory tumor control as well as limited radiation toxicity. Future prospective studies with long-term follow-up and comparison to single-session GKRS or fractionated stereotactic radiotherapy are necessary to validate these findings and determine the efficacy of this approach in the management of SBMs.

CyberKnife multisession stereotactic radiosurgery and hypofractionated stereotactic radiotherapy for perioptic meningiomas: intermediate-term results and radiobiological considerations

Single fraction radiosurgery is conventionally precluded for lesions lying <2-3 mm of the anterior visual pathway because of the radiosensitivity of the optic nerve. We analyzed a series of 64 patients with “perioptic” meningiomas treated by CyberKnife multisession radiosurgery and hypofractionated stereotactic radiotherapy (hSRT). Between July 2007-May 2010, patients were treated using conventional multisession Cyberknife schemes (2–5 fractions) and results were retrospectively analyzed. A radiobiological model was then developed to estimate the best tumor control probability (TCP)/ normal tissue complication probability (NTCP) for these lesions. Resulting dose/fraction schemes were applied to patients treated between May 2010 and July 2014. Data were prospectively collected

Twenty-five patients were included in the retrospective part of the study. Median tumor volume was 4.95 cc; median dose was 23.0 Gy and median number of fraction was 5 (range 2–5). No patient had visual deterioration at mean follow-up of 60 ± 12 months. Tumor control was achieved in all cases. Thirty-nine patients were treated according the radiobiology model and results prospectively analyzed. Median tumor volume was 7.5 cc, median dose 25.0 Gy and mean number of fraction 5 (range 3–15). No patient had visual deterioration or tumor progression at mean follow-up of 17 ± 10 months.

Conventional multisession CyberKnife treatments (2–5 fractions) provided satisfactory results. Nonetheless, our estimation of TCP suggests the use of higher doses to grant long-term disease control. To achieve higher equivalent doses without significantly increasing the NTCP, we suggest the use of a greater number of fractions, moving to hSRT, in tumors in which the encasement of optic nerves is presumed.

Gamma Knife radiosurgery for sellar and parasellar meningiomas: a multicenter study

Object

Parasellar and sellar meningiomas are challenging tumors owing in part to their proximity to important neurovascular and endocrine structures. Complete resection can be associated with significant morbidity, and incomplete resections are common. In this study, the authors evaluated the outcomes of parasellar and sellar meningiomas managed with Gamma Knife radiosurgery (GKRS) both as an adjunct to microsurgical removal or conventional radiation therapy and as a primary treatment modality.

Methods

A multicenter study of patients with benign sellar and parasellar meningiomas was conducted through the North American Gamma Knife Consortium. For the period spanning 1988 to 2011 at 10 centers, the authors identified all patients with sellar and/or parasellar meningiomas treated with GKRS. Patients were also required to have a minimum of 6 months of imaging and clinical follow-up after GKRS. Factors predictive of new neurological deficits following GKRS were assessed via univariate and multivariate analyses. Kaplan-Meier analysis and Cox multivariate regression analysis were used to assess factors predictive of tumor progression.

Results

The authors identified 763 patients with sellar and/or parasellar meningiomas treated with GKRS. Patients were assessed clinically and with neuroimaging at routine intervals following GKRS. There were 567 females (74.3%) and 196 males (25.7%) with a median age of 56 years (range 8–90 years). Three hundred fifty-five patients (50.7%) had undergone at least one resection before GKRS, and 3.8% had undergone prior radiation therapy. The median follow-up after GKRS was 66.7 months (range 6–216 months). At the last follow-up, tumor volumes remained stable or decreased in 90.2% of patients. Actuarial progression-free survival rates at 3, 5, 8, and 10 years were 98%, 95%, 88%, and 82%, respectively. More than one prior surgery, prior radiation therapy, or a tumor margin dose < 13 Gy significantly increased the likelihood of tumor progression after GKRS.

At the last clinical follow-up, 86.2% of patients demonstrated no change or improvement in their neurological condition, whereas 13.8% of patients experienced symptom progression. New or worsening cranial nerve deficits were seen in 9.6% of patients, with cranial nerve (CN) V being the most adversely affected nerve. Functional improvements in CNs, especially in CNs V and VI, were observed in 34% of patients with preexisting deficits. New or worsened endocrinopathies were demonstrated in 1.6% of patients; hypothyroidism was the most frequent deficiency. Unfavorable outcome with tumor growth and accompanying neurological decline was statistically more likely in patients with larger tumor volumes (p = 0.022) and more than 1 prior surgery (p = 0.021).

Conclusions

Gamma Knife radiosurgery provides a high rate of tumor control for patients with parasellar or sellar meningiomas, and tumor control is accompanied by neurological preservation or improvement in most patients.

Outcomes and complications of gamma knife radiosurgery for skull base meningiomas

Objective To review the outcomes and complications of meningiomas treated with gamma knife radiosurgery (GKRS) as a primary treatment as well as an adjunct therapy. Materials and Methods We performed a retrospective review (2000-2013) of 136 patients with meningiomas who received GKRS. Of 136 patients, 68 patients had recurrent or residual tumors after microsurgical resection, and the other 68 patients received GKRS alone. The study population was evaluated clinically and radiographically after GKRS treatment. Results GKRS in meningiomas showed significant variations in tumor growth control (decreased in 69 patients [50.7%], arrested growth in 47 patients [34.6%], and increased tumor size in 20 patients [14.7%]). Progression-free survival rates after GKRS at 3, 5, and 10 years were 98%, 95% and 85%, respectively. Overall improvement of signs and symptoms after GKRS was 30% (71% versus 41%) compared with pretreated sign and symptoms (p = 0.0001). The Karnofsky performance scale was significantly improved after GKRS compared with the pretreated status (92 versus 80). Twenty patients (14.7%) required resection after initial GKRS. Conclusion These study findings revealed that GKRS offers a high rate of tumor control, preservation of multiple nerve functions, and a good quality of life in both new and recurrent patients with meningiomas.

Fractionated radiation therapy for vestibular schwannoma

Vestibular schwannomas are the most common tumors of the cerebellopontine angle. Multiple management paradigms exist for patients with these benign tumors, including observation, microsurgery, stereotactic radiosurgery, and fractionated radiation therapy, or some combination of these. While the proper course of management is controversial, the goals of therapy are to achieve excellent local tumor control and optimize functional outcomes with as little treatment-related morbidity as possible. Decision-making is tailored to patient-specific factors such as tumor size, clinical presentation, patient age, and goals of hearing preservation. We review the literature in order to summarize the application of fractionated radiation therapy to this tumor entity, where it is used as a primary treatment or, more commonly, as an adjunct therapy. We also provide an overview of the use of fractionated radiation therapy for the preservation of hearing and facial function, and dosing and other technical considerations, in light of the indolent natural history of vestibular schwannomas. We also discuss potential risks associated with this treatment modality, including its effects on temporal bone structures and cranial nerves among other possible complications. Lastly, we outline future directions in this rapidly evolving segment of vestibular schwannoma therapy, which has benefited from the advent of intensity-modulated radiation therapy coupled with stereotactic localization.

Benign orbital apex tumors treated with multisession gamma knife radiosurgery

OBJECTIVE

The orbital apex is an important anatomic landmark that hosts numerous critical neurovascular structures. Tumor resection performed at this complex region poses a therapeutic challenge to orbital surgeons and often is associated with significant visual morbidity. This article reports the efficacy and safety of multisession gamma knife radiosurgery (GKRS) in benign, well-circumscribed tumors located at the orbital apex.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Five patients with visual disturbances resulting from a benign, well-circumscribed orbital apex tumor (3 cases of cavernous hemangioma and 2 cases of schwannoma).

METHODS

Each patient treated with GKRS with a total radiation dose of 20 Gy in 4 sessions (5 Gy in each session with an isodose line of 50%) delivered to the tumor margin.

MAIN OUTCOME MEASURES

Best-corrected visual acuity, visual field changes, orbital imaging, tumor growth control, and side effects of radiation.

RESULTS

All patients demonstrated improvement in visual acuity, pupillary responses, color vision, and visual field. Tumor shrinkage was observed in all patients and remained stable until the last follow-up. No adverse events were noted during or after the radiosurgery. None of the patients experienced any radiation-related ocular morbidity.

CONCLUSIONS

From this experience, multisession GKRS seems to be an effective management strategy to treat solitary, benign, well-circumscribed orbital apex tumors.

Gamma knife surgery for skull base meningiomas

OBJECT

Skull base meningiomas are challenging tumors owing in part to their close proximity to important neurovascular structures. Complete microsurgical resection can be associated with significant morbidity, and recurrence rates are not inconsequential. In this study, the authors evaluate the outcomes of skull base meningiomas treated with Gamma Knife surgery (GKS) both as an adjunct to microsurgery and as a primary treatment modality.

METHODS

The authors performed a retrospective review of a prospectively compiled database detailing the outcomes in 255 patients with skull base meningiomas treated at the University of Virginia from 1989 to 2006. All patients had a minimum follow-up of 24 months. The group comprised 54 male and 201 female patients, with a median age of 55 years (range 19-85 years). One hundred nine patients were treated with upfront radiosurgery, and 146 patients were treated with GKS following resection. Patients were assessed clinically and radiographically at routine intervals following GKS. Factors predictive of new neurological deficit following GKS were assessed via univariate and multivariate analysis, and Kaplan-Meier analysis and Cox multivariate regression analysis were used to assess factors predictive of tumor progression.

RESULTS

Meningiomas were centered over the cerebellopontine angle in 43 patients (17%), the clivus in 40 (16%), the petroclival region in 28 (11%), the petrous region in 6 (2%), and the parasellar region in 138 (54%). The median duration of follow-up was 6.5 years (range 2-18 years). The mean preradiosurgery tumor volume was 5.0 cm(3) (range 0.3-54.8 cm(3)). At most recent follow-up, 220 patients (86%) displayed either no change or a decrease in tumor volume, and 35 (14%) displayed an increase in volume. Actuarial progression-free survival at 3, 5, and 10 years was 99%, 96%, and 79%, respectively. In Cox multivariate analysis, pre-GKS covariates associated with tumor progression included age greater then 65 years (HR 3.41, 95% CI 1.63-7.13, p = 0.001) and decreasing dose to tumor margin (HR 0.90, 95% CI 0.80-1.00, p = 0.05). At most recent clinical follow-up, 230 patients (90%) demonstrated no change or improvement in their neurological condition and the condition of 25 patients had deteriorated (10%). In multivariate analysis, the factors predictive of new or worsening symptoms were increasing duration of follow-up (OR 1.01, 95% CI 1.00-1.02, p = 0.015), tumor progression (OR 2.91, 95% CI 1.60-5.31, p < 0.001), decreasing maximum dose (OR 0.90, 95% CI 0.84-0.97, p = 0.007), and petrous or clival location versus parasellar, petroclival, and cerebellopontine angle location (OR 3.47, 95% CI 1.23-9.74, p = 0.018).

CONCLUSIONS

Stereotactic radiosurgery offers a high rate of tumor control and neurological preservation in patients with skull base meningiomas. After radiosurgery, better outcomes were observed for those receiving an optimal radiosurgery dose and harboring tumors located in a cerebellopontine angle, parasellar, or petroclival location.

Evolution and future of skull base surgery: the paradigm of skull base meningiomas

BACKGROUND

Skull base meningiomas represent the paradigm for the evolution of skull base surgery within the past 50 years into a distinct neurosurgical subspecialty.

METHODS

From 2005 to 2011, 117 patients with cranial base meningiomas underwent surgical resection. Extent of resection, histologic grade, complications, functional status, and recurrence-free and overall survival data are presented.

RESULTS

The summary rate of gross total resection was 53.0%. The surgical complication and mortality rates were 17.9% and 0.9%, respectively. Five-year recurrence-free survival was 88.0% for grade I meningiomas. A total of 90.3% of patients had a Karnofsky performance score ≥ 80 at last follow-up.

CONCLUSIONS

A large contemporary series of skull base meningiomas is presented. In addition, the evolution of surgical approaches to skull base meningiomas is reviewed, together with the current issues regarding radiation therapy, management of cavernous sinus tumor, oncologic management of atypical and malignant subtypes, molecular genetics, and future therapeutic options.

Fractionated stereotactic conformal radiotherapy for large benign skull base meningiomas

Purpose

to assess the safety and efficacy of fractionated stereotactic radiotherapy (FSRT) for large skull base meningiomas.

Methods and Materials

Fifty-two patients with large skull base meningiomas aged 34-74 years (median age 56 years) were treated with FSRT between June 2004 and August 2009. All patients received FSRT for residual or progressive meningiomas more than 4 centimeters in greatest dimension. The median GTV was 35.4 cm³ (range 24.1-94.9 cm³), and the median PTV was 47.6 cm³ (range 33.5-142.7 cm³). Treatment volumes were achieved with 5-8 noncoplanar beams shaped using a micromultileaf collimator (MLC). Treatment was delivered in 30 daily fractions over 6 weeks to a total dose of 50 Gy using 6 MV photons. Outcome was assessed prospectively.

Results

At a median follow-up of 42 months (range 9-72 months) the 3-year and 5-year progression-free survival (PFS) rates were 96% and 93%, respectively, and survival was 100%. Three patients required further debulking surgery for progressive disease. Hypopituitarism was the most commonly reported late complication, with a new hormone pituitary deficit occurring in 10 (19%) of patients. Clinically significant late neurological toxicity was observed in 3 (5.5%) patients consisting of worsening of pre-existing cranial deficits.

Conclusion

FSRT as a high-precision technique of localized RT is suitable for the treatment of large skull base meningiomas. The local control is comparable to that reported following conventional external beam RT. Longer follow-up is required to assess long term efficacy and toxicity, particularly in terms of potential reduction of treatment-related late toxicity.

Significance of tumor volume related to peritumoral edema in intracranial meningioma treated with extreme hypofractionated stereotactic radiation therapy in three to five fractions

BACKGROUND

To investigate the treatment results of intracranial meningiomas treated with hypofractionated stereotactic radiation therapy in three to five fractions.

METHODS

Thirty-one patients (32 lesions) with intracranial meningioma were treated with hypofractionated stereotactic radiation therapy in three to five fractions using CyberKnife. Fifteen lesions were diagnosed as Grade I (World Health Organization classification) by surgical resection and 17 lesions were diagnosed as meningioma based on radiological findings. The median follow-up time was 48 months. The median planning target volume was 6.3 cm(3) (range, 1.4-27.1), and the prescribed dose (D90≤) ranged from 21 to 36 Gy (median, 27.8) administrated in three to five fractions.

RESULTS

Five-year overall and progression-free survival rate of all 31 patients with intracranial meningioma was 86 and 83%, respectively. Five-year progression-free rate of all 32 lesions was 87%. Six of the 31 patients (19%) developed marked peritumoral edema, three of whom were asymptomatic and three symptomatic, the latter with late adverse effects of more than or equal to Grade 3. The mean planning target volume of the six lesions with marked peritumoral edema was 15.6 cm(3), and for the remaining 26 lesions without marked peritumoral edema was 7.1 cm(3) (P = 0.004). The threshold diameter of 2.56 cm for meningioma was calculated from the planning target volume (11 cm(3)) and was used as marker of developing peritumoral edema (P = 0.003).

CONCLUSIONS

Tumor volume is a significant indicative factor for peritumoral edema in intracranial meningioma treated with hypofractionated stereotactic radiation therapy in three to five factions.

MULTISESSION CYBERKNIFE STEREOTACTIC RADIOSURGERY OF LARGE, BENIGN CRANIAL BASE TUMORS

OBJECTIVE

Although radiosurgery plays an important role in managing benign cranial base lesions, the potential for increased toxicity with single-session treatment of large tumors is a concern. In this retrospective study, we report the intermediate-term rate of local control, morbidity, and clinical outcomes of patients with large cranial base tumors treated with multisession stereotactic radiosurgery with the CyberKnife (Accuray, Inc., Sunnyvale, CA).

METHODS

Between 1999 and 2008, 34 consecutive patients with large (&gt;15 cm3), benign cranial base tumors (21 meningiomas, 9 schwannomas, 4 glomus jugulare tumors) underwent primary or postoperative radiosurgical treatment using a multisession approach at Stanford University and were considered in this retrospective study. Forty-four percent of these patients had undergone previous subtotal surgical resection or radiotherapy. CyberKnife radiosurgery was delivered in 2 to 5 sessions (median, 3 sessions) to a median tumor volume of 19.3 cm3 (range, 15.8–69.3 cm3). The median marginal dose was 24 Gy (range, 18–25 Gy) prescribed to a median 78% isodose line.

RESULTS

After a median clinical follow-up of 31 months (range, 12–77 months), 21% of patients experienced clinical improvement of neurological symptoms, whereas neurological status remained unchanged among the rest. Four patients experienced prolonged use of glucocorticoids owing to transient neurological worsening and radiographic signs of radiation injury. No permanent neurotoxicity was seen. To date, all tumors remain locally controlled.

CONCLUSION

Over our modest length of follow-up, multisession radiosurgery appears to be a safe and effective option for selected large, benign brain and cranial base lesions.

Radiotherapy and radiosurgery for benign skull base meningiomas

Meningiomas located in the region of the base of skull are difficult to access. Complex combined surgical approaches are more likely to achieve complete tumor removal, but frequently at a cost of treatment related high morbidity. Local control following subtotal excision of benign meningiomas can be improved with conventional fractionated external beam radiation therapy with a reported 5-year progression-free survival up to 95%. New radiation techniques, including stereotactic radiosurgery (SRS), fractionated stereotactic radiotherapy (FSRT), and intensity-modulated radiotherapy (IMRT) have been developed as a more accurate technique of irradiation with more precise tumor localization, and consequently a reduction in the volume of normal brain irradiated to high radiation doses. SRS achieves a high tumour control rate in the range of 85-97% at 5 years, although it should be recommended only for tumors less than 3 cm away more than 3 mm from the optic pathway because of high risk of long-term neurological deficits. Fractionated RT delivered as FSRT, IMRT and protons is useful for larger and irregularly or complex-shaped skull base meningiomas close to critical structures not suitable for single-fraction SRS. The reported results indicate a high tumour control rate in the range of 85-100% at 5 years with a low risk of significant incidence of long-term toxicity. Because of the long natural history of benign meningiomas, larger series and longer follow-up are necessary to compare results and toxicity of different techniques.

Radiosurgery as definitive management of intracranial meningiomas

OBJECTIVE

Stereotactic radiosurgery has become an important primary or adjuvant minimally invasive management strategy for patients with intracranial meningiomas with the goals of long-term tumor growth prevention and maintenance of patient neurological function. We evaluated clinical and imaging outcomes of meningiomas stratified by histological tumor grade.

METHODS

The patient cohort consisted of 972 patients with 1045 intracranial meningiomas managed during an 18-year period. The series included 70% women, 49% of whom had undergone a previous resection and 5% of whom had received previous fractionated radiation therapy. Tumor locations included middle fossa (n = 351), posterior fossa (n = 307), convexity (n = 126), anterior fossa (n = 88), parasagittal region (n = 113), or other (n = 115).

RESULTS

The overall control rate for patients with benign meningiomas (World Health Organization Grade I) was 93%. In those without previous histological confirmation (n = 482), tumor control was 97%. However, for patients with World Health Organization Grade II and III tumors, tumor control was 50 and 17%, respectively. Delayed resection after radiosurgery was necessary in 51 patients (5%) at a mean of 35 months. After 10 years, Grade 1 tumors were controlled in 91% (n = 53); in those without histology, 95% (n = 22) were controlled. None of the patients developed a radiation-induced tumor. The overall morbidity rate was 7.7%. Symptomatic peritumoral imaging changes developed in 4% of the patients at a mean of 8 months.

CONCLUSION

Stereotactic radiosurgery provided high rates of tumor growth control or regression in patients with benign meningiomas with low risk. This study confirms the role of radiosurgery as an effective management choice for patients with small to medium-sized symptomatic, newly diagnosed or recurrent meningiomas of the brain.

Meningioma

Meningiomas are mostly benign tumours originating from the arachnoid cap cells, represent 13-26% of all intracranial tumours. They are more common in older age and in females. Deletion in NF2 gene and exposure to ionizing radiation are established risk factors, while the role of sex hormones is yet not clarified. Five-year survival for typical meningiomas exceeds 80%, but is poorer (5-year survival <60%) in malignant and atypical meningiomas. Papillary and haemangiopericytic morphology, large tumour size, high mitotic index, absence of progesterone receptors, deletions and loss of heterozygosity are poor prognostic factors. Complete surgical excision is the standard treatment. Radiotherapy is currently used in the clinical practice in atypical, malignant or recurrent meningioma at a total dose of 45-60Gy. However, the role of adjuvant irradiation is still controversial and has to be compared in a randomised prospective setting with a policy of watchful waiting. Radiosurgery has gained more and more importance in the management of meningiomas, especially in meningiomas that cannot be completely resected as for many skull base meningiomas. Medical therapy for patients with recurrent, progressive and symptomatic disease after repeated surgery, radiosurgery and radiotherapy is investigational. Hormonal therapy with progesterone antagonists has shown modest results, while chemotherapy with hydroxyurea appears moderately active.

Transpetrosal approaches for meningiomas of the posterior aspect of the petrous bone

OBJECTIVE

To assess outcome following excision of meningiomas of the posterior aspect of the petrous bone through transpetrosal approaches.

MATERIAL AND METHOD

We carried out a retrospective case-series study in a multidisciplinary tertiary care center on all patients who underwent meningiomas removal from January 1989 to September 2005. Surgical approaches were transpetrosal: widened retrolabyrinthine, translabyrinthine, transotic and transcochlear, occasionally combined with a subtemporal transtentorial approach. Epidemiology, symptoms, preoperative evaluation, surgery, postoperative complications and facial and auditory results were analyzed using standardized grading systems. The Desgeorges and Sterkers classification was used to assess tumor size and location.

RESULTS

Forty women and three men underwent surgery (mean age: 56.7). Medium-sized tumors stages 2 and 3 (84%) and AM and P localization (34% and 20.4%) predominated. In 65% of cases, the tumor extended beyond the CPA. Main presenting symptoms were balance disorders (72%) and sensorineural hearing loss (53.5%). Mortality was nil. A preoperative facial nerve paresis was present in 14% of patients. Tumor removal was complete in 79.1% of cases. At 1-year post-op, 73% of patients had a normal or subnormal facial function and 55% had serviceable hearing. A cerebrospinal fluid leakage occurred in 6.9%.

DISCUSSION

Posteriorly attached meningiomas are less symptomatic and of better prognosis than medially inserted ones. Transpetrosal approaches are reliable for the removal for all types and sizes of such tumors, and can be easily combined in the same procedure with a subtemporal transtentorial approach to remove extensions to the clivus and tentorium. They offer low morbidity and a high proportion of facial nerve and hearing preservation.

Gamma Knife surgery for benign meningioma

Object

Meningioma is the most frequent benign tumor treated with Gamma Knife surgery (GKS); however, the assessment of its efficacy and safety in slow-growing tumors is an ongoing process, requiring analysis of long-term results.

Methods

Three hundred sixty-eight patients harboring 400 meningiomas treated between 1992 and 1999 at Na Homolce Hospital were evaluated. The median patient age was 57 years (range 18–84 years). The median tumor volume was 4.4 cm3 (range 0.11–44.9 cm3). The median tumor margin dose to the 50% isodose line was 12.55 Gy (range 6.5–24 Gy). Descriptive analysis was performed in 331 patients (90%); 325 patients had a follow-up longer than 24 months (median 60 months), and six patients were included because of posttreatment complications. The volume of treated tumors decreased in 248 cases (69.7%), remained the same in 99 (27.8%), and increased in nine (2.5%). The actuarial tumor control rate was 97.9% at 5 years post-GKS. Perilesional edema after radiosurgery was confirmed on neuroim-aging in 51 patients (15.4%). The temporary and permanent morbidity rates after radiosurgery were 10.2 and 5.7%, respectively.

Results

A significantly higher incidence of tumor volume increase was observed in men compared with women and in tumors treated with a margin dose lower than 12 Gy. Significant risk factors for edema included an age greater than 60 years, no previous surgery, perilesional edema before radiosurgery, a tumor volume greater than 10 cm3, a tumor location in the anterior fossa, and a margin dose greater than 16 Gy.

Conclusions

Stereotactic radiosurgery is a safe method of treatment for meningiomas. A minimum margin dose of 12 to 16 Gy seems to represent the therapeutic window for benign meningiomas with a high tumor control rate in a mid-term follow-up period.

Visual field preservation after multisession cyberknife radiosurgery for perioptic lesions

OBJECTIVE

The restricted radiation tolerance of the anterior visual pathways represents a unique challenge for ablating adjacent lesions with single-session radiosurgery. Although preliminary studies have recently demonstrated that multisession radiosurgery for selected perioptic tumors is both safe and effective, the number of patients in these clinical series was modest and the length of follow-up limited. The current retrospective study is intended to help address these shortcomings.

METHODS

Forty-nine consecutive patients with meningioma (n = 27), pituitary adenoma (n = 19), craniopharyngioma (n = 2), or mixed germ cell tumor (n = 1) situated within 2 mm of a "short segment" of the optic apparatus underwent multisession image-guided radiosurgery at Stanford University Medical Center. Thirty-nine of these patients had previous subtotal surgical resection, and six had previously been treated with conventional fractionated radiotherapy (6). CyberKnife radiosurgery was delivered in two to five sessions to an average tumor volume of 7.7 cm3 and a cumulative average marginal dose of 20.3 Gy. Formal visual testing and clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months.

RESULTS

After a mean visual field follow-up of 49 months (range, 6-96 mo), vision was unchanged postradiosurgery in 38 patients, improved in eight (16%), and worse in three (6%). In each instance, visual deterioration was accompanied by tumor progression that ultimately resulted in patient death. However, one of these patients, who had a multiply recurrent adrenocorticotropic hormone-secreting pituitary adenoma, initially experienced early visual loss without significant tumor progression after both a previous course of radiotherapy and three separate sessions of radiosurgery. After a mean magnetic resonance imaging follow-up period of 46 months, tumor volume was stable or smaller in all other cases. Two patients died of unrelated nonbrain causes.

CONCLUSION

Multisession radiosurgery resulted in high rates of tumor control and preservation of visual function in this group of perioptic tumors. Ninety-four percent of patients retained or improved preradiosurgical vision. This intermediate-term experience reinforces the findings from earlier studies that suggested that multisession radiosurgery can be a safe and effective alternative to either surgery or fractionated radiotherapy for selected lesions immediately adjacent to short segments of the optic apparatus.

Interinstitutional variance of postoperative radiotherapy and follow up for meningiomas in Germany: impact of changes of the WHO classification

OBJECTIVE

To document and critically analyse the impact of the revised WHO 2000 histological classification for meningiomas on postoperative radiotherapy/radiosurgery indications and MRI follow up protocols.

METHODS

The current (2000) WHO classification was used to grade 57 meningiomas treated surgically at one institution. These had been reviewed previously in 1999. All German neurosurgical departments carrying out intracranial microsurgery were asked to detail their guidelines for radiation therapy and follow up for meningiomas of different WHO grades.

RESULTS

Use of the current criteria downgraded seven of 15 atypical meningiomas (WHO grade II, MII) to grade I (MI), and four of six anaplastic tumours (WHO grade III, MIII) to grade II. Indications for radiotherapy/radiosurgery and MRI follow up protocols varied substantially with the histological grade and between institutions--for example, after an incomplete resection, radiotherapy/radiosurgery recommendations differed between MI and MII in 30 of 58 units (52%), and between MII and MIII in 34 of 56 units (61%).

CONCLUSIONS

Correlative studies combining treatment and outcome data with a standardised histopathological analysis are warranted to define properly the indications for radiotherapy/radiosurgery and follow up protocols after surgery for meningiomas of different histological grades. The use of changing grading paradigms during recent years renders decision making based on local and published experience difficult. The relatively large number of meningiomas classified as atypical/WHO grade II in current practice would argue against an uncritically aggressive approach to these tumours.

Evaluation of fractionated radiotherapy and gamma knife radiosurgery in cavernous sinus meningiomas: treatment strategy

OBJECTIVE

To investigate the respective role of fractionated radiotherapy (FR) and gamma knife stereotactic (GKS) radiosurgery in cavernous sinus meningioma (CSM) treatment.

METHODS

The authors report the long-term follow-up of two populations of patients harboring CSMs treated either by FR (Group I, 38 patients) or GKS radiosurgery (Group II, 36 patients). There were 31 females with a mean age of 53 years in Group I and 29 females with a mean age of 51.2 years in Group II. In 20 patients (Group I) and 13 patients (Group II), FR and GKS radiosurgery were performed as an adjuvant treatment. In 18 patients (Group I) and in 23 patients (Group II), FR and GKS radiosurgery were performed as first line treatment. In our early experience with GKS radiosurgery (1992, date of gamma knife availability in the department), patients with tumors greater than 3 cm, showing close relationship with the optic apparatus (<3 mm) or skull base dural spreading, were treated by FR. Secondarily, with the advent of new devices and our growing experience, these criteria have evolved.

RESULTS

The median follow-up period was 88.6 months (range, 42-168 mo) for Group I and 63.6 months (range, 48-92 mo) for Group II. According to Sekhar's classification, 26 (68.4%) patients were Grade III to IV in Group I and 10 (27.8%) patients in Group II (P < 0.05); 23 (60.5%) patients had extensive lesions in Group I and 7 (19.4%) patients in Group II (P < 0.05). Mean tumor volume was 13.5 cm in Group I and 5.2 cm in Group II (P < 0.05). Actuarial progression-free survival was 94.7% and 94.4% in Group I and II, respectively. Clinically, improvement was seen for 24 (63.2%) patients in Group I and for 21 (53.8%) patients in Group II (P > 0.05). Radiologically, 11 (29%, Group I) patients and 19 (Group II, 52.7%) patients showed tumor shrinkage (P = 0.04). Transient morbidity was 10.5% in Group I and 2.8% in Group II. Permanent morbidity was 2.6% in Group I and 0% in Group II.

CONCLUSION

FR and GKS radiosurgery are safe and efficient techniques in treatment of CSMs, affording comparable satisfactory long-term tumor control. However, GKS radiosurgery provides better radiological response, is far more convenient, and fits into most patients lives much better than FR. Therefore, in the authors' opinion, GKS radiosurgery should be advocated in first intention for patients with CSMs, whereas conventional radiotherapy should be reserved for cases that are not amenable to this technique, thus making these two therapeutic modalities not alternative but complementary tools in CS meningioma treatment strategy.

Meningioma

Total excision is an appropriate treatment option for patients with benign meningiomas that are resectable with minimal morbidity. It is particularly appropriate for patients with significant mass effect causing symptoms. Fractionated conformal radiotherapy is an appropriate primary treatment option for patients with benign meningiomas of all sizes and all sites. It is particularly appropriate and preferred for optic nerve sheath meningiomas, for which there are few alternatives. Planned subtotal resection is appropriate if decompression is expected to relieve acute symptoms. After subtotal resection, it is appropriate to offer single-fraction radiosurgery or multifraction radiotherapy, depending on the size, location, and extent of residual tumor, so as to achieve progression-free survival and cause-specific survival rates comparable to those of other approaches.

Fractionated stereotactic radiotherapy in the treatment of exclusive cavernous sinus meningioma: functional outcome, local control, and tolerance

BACKGROUND

Fractionated stereotactic radiotherapy (FSRT) combines the precision of stereotactic positioning with the radiobiologic advantage of dose fractionation.

METHODS

From June 1997 to June 2001, 30 patients with cavernous sinus meningiomas were treated with FSRT using fixed noncoplanar conformal fields. Patient skull fixation was achieved using the BrainLAB mask (20 patients) or Beverly frame (10 patients). The Cosman-Roberts-Wells coordinate frame was used for stereotactic space definition. In selected cases before 1999, and in all cases afterward, gadolinium-enhanced MRI for image fusion was performed. The median radiation dose was 52 Gy, with a daily fraction of 2 Gy. Patients were regularly followed up analyzing symptoms, tumor progression, and side effects. Neurocognitive function was evaluated retrospectively for 26 patients using Mini-Mental State Examination.

RESULTS

Median follow-up period was 50 months (range, 28.2-74.5 months). Preexisting neurologic symptoms improved in 50% of the patients and worsened in 2 patients. Only 2 patients progressed and the actuarial local progression free survival was 93% at 4 years. Tolerance was good with 2 cases of late radiation toxicity which consisted of moderate short-term memory loss and dysphasia in one case and neuropsychologic deficit with seizures in the other. Postradiotherapy Mini-Mental State Examination results showed a median score of 28 (range, 16-30).

CONCLUSIONS

Fractionated stereotactic radiotherapy is a high-precision technique. It is safe and feasible in the primary and adjuvant treatment of cavernous sinus meningiomas. Fractionated stereotactic radiotherapy allowed local control in more than 90% of patients.

Pushing the limits of radiotherapy for atypical and malignant meningioma

PURPOSE

The purpose of this study was to report the outcome of an extremely aggressive radiotherapy program in patients with atypical and malignant meningioma (60 Gy at 1.5 Gy per fraction twice daily +/- radiosurgery boost).

METHODS AND MATERIALS

Thirty-six patients received radiotherapy with curative intent between 1984 and 1999 for atypical (27 patients) or malignant (9 patients) meningioma. All patients had a minimum of 2 years follow up.

RESULTS

The overall 5-year local control, cause-specific survival, and absolute survival rates were 45%, 39%, and 36%, respectively. Accelerated hyperfractionated radiotherapy resulted in a local control rate of 45% compared with 50% for patients treated with less aggressive schedules (P = 0.99). A radiosurgery boost did not improve tumor control. The complication rate for those treated with accelerated hyperfractionated radiotherapy was dramatically higher (grade 3-5: 55% vs. 0%, grade 4-5: 27% vs. 0%. both P <0.05).

CONCLUSION

Our data suggests that 50 to 60 Gy delivered with conventional, once-daily fractionation is probably the optimal schedule for atypical and malignant meningioma. More aggressive radiotherapy fractionation schedules and radiosurgery are unlikely to improve outcome.

Functional outcome of patients with benign meningioma treated by 3D conformal irradiation with a combination of photons and protons

PURPOSE

To evaluate efficacy and tolerance of external fractionated combination of photon and proton radiation therapy (RT) for intracranial benign meningiomas.

METHODS AND MATERIALS

Between 1994 and 2002, 51 patients with intracranial meningiomas of the base of the skull were treated with a combination of photon and proton RT. Median total dose was 60.6 cobalt Gy equivalent (54-64). One hundred eight eye-related symptoms were collected; 80 other symptoms were noted and followed up.

RESULTS

Mean follow-up was 25.4 months. Acute tolerance was excellent. Out of the 108 eye-related symptoms, 106 (96%) were evaluated. Improvements were reported for 73 (68.8%) of them. Out of the 88 other miscellaneous symptoms, 81 (92%) were evaluated. Improvements were reported in 54 cases (67%). Median time to improvement ranged from 1 to 24 months after completion of the radiotherapy, depending on the symptom. We did not observe any worsening of primary clinical signs. Radiologically, 1 patient relapsed 4 months after the end of irradiation. Pathology revealed a malignant (Grade 3) transformation of the initial Grade 1 meningioma. Four-year local control and overall survival rates were, respectively, 98% and 100%. Stabilization of the tumor was observed in 38 cases (72%), volume reduction in 10 cases (20%), and intratumor necrosis in 3 cases. Two patients complained of Grade 3 side effects: 1 unilateral hearing loss requiring aid and 1 case of complete pituitary deficiency.

CONCLUSION

These results stressed the clinical efficacy of fractionated-associated photon-proton RT in the treatment of meningiomas, especially on cranial nerve palsies, without severe toxicity in almost all patients.

Primary radiotherapy for optic nerve sheath meningioma

Radiotherapy has recently been recognized as the treatment of choice for most primary optic nerve sheath meningiomas (ONSM). Radiotherapy is incorporated into the treatment of non optic nerve sheath meningiomas for unresectable or subtotally resected tumors. Most primary ONSM are not surgically approachable without a high risk of visual deterioration. Radiotherapy has been found to prevent or delay tumor growth for the majority of patients and improve vision in some. We review the rational and current methods of the use of radiotherapy for these tumors.

Adjuvant gamma knife radiosurgery after meningioma resection

We evaluated the usefulness of adjuvant treatment with gamma knife radiosurgery following meningioma surgery. During the past 8 years, we operated on 78 patients with meningiomas. Among these, 28 patients (36%) received gamma knife radiosurgery postoperatively. The indications for radiosurgery were as follows: residual tumour after surgery in 13 patients (46.4%), regrowth of residual tumour during the follow-up period in 7 patients (25%), recurrence after total removal (Simpson grade 1 or 2) in 7 patients (25%), and another intracranial meningioma in one patient (3.6%). The tumour diameter at the time of radiosurgery ranged from 5.2 to 48.1 mm (median 21.6 mm). Larger tumours with a mean diameter above 40 mm in two patients were treated with two-staged radiosurgery. The tumor marginal dose ranged from 8 to 23 Gy (median 12 Gy). The follow-up period was 3-84 months (median 30 months) after radiosurgery. The tumour size decreased in 17 patients (60.7%), remained unchanged in 9 patients (32.1%), and increased in 2 patients (7.2%). No radiation injury was experienced. Adjuvant therapy using gamma knife radiosurgery for meningiomas can achieve control of tumour growth and may improve patient outcomes. Careful surgical planning and follow-up are required to understand the usefulness and limitations of radiosurgery in this setting.

Traitement des méningiomes par hydroxyurée

BACKGROUND

Management of unresectable progressive meningioma remains controversial and constitutes a major challenge since therapeutic options including chemotherapy and hormone modulation are limited. Recent data have suggested that hydroxyurea treatment may have an antitumoral effect. The purpose of this prospective phase II study was to evaluate the efficacy of hydroxyurea treatment for unresectable progressive meningioma.

METHODS

From 1997 to 1999, consecutive patients presenting unresectable meningioma with clinically and/or neuroradiologically documented progression were considered for entry into this protocol. Previous radiotherapy was not a mandatory inclusion criteria. Treatment consisted of continuous oral administration of hydroxyurea at a dose of 20 mg/kg per day. Follow-up assessment included physical examination, computed tomography (CT), and magnetic resonance imaging (MRI) performed every three months, as well as regular blood testing. The primary endpoint was documentation of objective response by MRI or CT.

RESULTS

The intent-to-treat population was 43 patients with at least 18 months follow-up. Median age was 60.4 years. Twenty-eight patients had undergone surgery following initial diagnosis. The meningioma was located in the skull base in 67% of patients. Histology was benign in 18 and atypical in 10. The eligible population included 36 patients with documented progressive disease at the time of inclusion; with progression documented clinically in 29 (67.5%) and/or radiologically in 20 (46%). In 7 patients, clinical or radiological progression could not be confirmed. The intent-to-treat analysis at median 26 months follow-up revealed objective response to hydroxyurea in only 3 patients (7%) including one on the basis of improvement in visual symptoms and two on MRI analysis. Progressive disease was observed clinically or radiologically in 26 patients (60.5%). Of the eligible population (n=36), 2 achieved an objective response and 13 (36%) exhibited stabilization under hydroxyurea therapy, while 21 (58%) progressed under treatment. Overall tolerance was good but anemia (grade I-II) and asthenia (grade I-II) were observed in 28% and 23.5% respectively. Treatment was discontinued in 3 patients because of chronic skin toxicity in one and anemia and asthenia in two.

CONCLUSION

Hydroxyurea treatment is of marginal efficacy for meningioma and must not be considered as an alternative if radiotherapy or surgery is feasible. New efficient medical treatments are still required for progressive meningiomas.

Radiotherapy after surgery for benign cerebral meningioma

BACKGROUND AND PURPOSE

To compare the outcome from adjuvant and delayed radiotherapy (RT) after surgery in patients with benign cerebral meningioma.

PATIENTS AND METHODS

Between March 1953 and January 2001, 92 patients with benign cerebral meningioma (WHO grade I) were treated with surgery. Forty-eight patients underwent gross total resection (GTR), and 44 patients underwent subtotal resection (STR). Treatments were classified as GTR (n = 48), STR+adjuvant RT (n = 12), STR alone (n = 32). The prognostic factors were assessed as, gender, the Karnofsky performance score (KPS) (> or =90 vs. <90), the extent of surgery, and adjuvant or delayed RT. The endpoints analyzed were progression-free survival (PFS) and overall survival (OS). Overall survival curve of the study population is compared with the age-adjusted expected survival curve for the US population born in 1970.

RESULTS

The median follow-up was 7.7 years. The 5-year PFS and OS rates for all patients were 65 and 93%, respectively. The 5-year PFS rates in patients treated with GTR and STR were 77 and 52%, respectively (P = 0.02). Patients treated with STR+adjuvant RT had significantly better PFS (91%) at 5 years than with STR alone (38%) (P = 0.0005). Gender showed no statistically significant impact on either PFS or OS (P > 0.05). However, multivariate analysis showed the KPS to have a statistically significant effect on OS (P = 0.02). The OS rate was the same across all three treatment groups. The age-adjusted expected survival curve for the US population born in 1970 lay within the confidence intervals for the overall survival curve of the study population.

CONCLUSIONS

Although OS was not affected, adjuvant RT appeared to significantly reduce tumor progression. However, only a prospective randomized trial can adequately determine whether adjuvant or delayed radiotherapy is the better approach in patients with subtotally resected benign meningioma.

GAMMA KNIFE RADIOSURGERY FOR BENIGN CAVERNOUS SINUS TUMORS: QUANTITATIVE ANALYSIS OF TREATMENT OUTCOMES

OBJECTIVE

We review our 8-year experience with gamma knife radiosurgery (GKRS) for the treatment of patients with benign cavernous sinus tumors and present a quantitative analysis of factors relevant to treatment outcomes.

METHODS

From 1994 to 2002, a total of 139 patients with benign cavernous sinus tumors were treated in 145 sessions. Their median age was 53 years, and the median follow-up was 3.5 years. The tumors included 57 meningiomas, 76 pituitary tumors (49 nonfunctional adenomas, 15 prolactinomas, 5 adrenocorticotropic hormone-secreting tumors, 6 growth hormone-secreting tumors, and 1 plurihormone-secreting tumor), 4 schwannomas, 1 hemangioma, and 1 paraganglioma. Sekhar tumor grades were as follows: I, n = 28 (20%); II, n = 42 (30%); III, n = 42 (30%); IV, n = 19 (14%); and V, n = 8 (6%). The median tumor volume was 3.4 cm(3), and the median prescribed dose was 15 Gy defined to the 50% isodose line.

RESULTS

A total of 136 treated tumors (97.8%) were well controlled by GKRS, with low morbidity. For meningiomas, 29 tumors (51%) were unchanged and 26 (46%) were smaller at a median of 15.2 months. For pituitary tumors, 50 (66%) were unchanged and 25 (33%) were smaller at a median of 20.6 months. Improvement in cranial nerve (CN) function was seen in 19 (36.5%) of 52 patients with pre-GKRS deficits, and 3 patients (2.2%) developed new stable CN deficits after GKRS: 1 patient developed IVth CN palsy at 9 months, and 2 developed persistent VIth CN palsies at 43 and 45 months, respectively, that required surgical correction. Two patients developed transient VIth CN palsies at 48 months that self-resolved after another year. Endocrine function normalized for all 6 treated patients with a growth hormone-secreting tumor at a median of 18 months. One of the 5 adrenocorticotropic hormone-secreting tumors required retreatment after 17 months because of continued cortisol elevation. Thirteen (87%) of 15 prolactinoma patients had normalized prolactin levels within 2 years of the procedure; 2 patients relapsed by endocrine criteria at 18 and 22 months after GKRS. Two patients with normalized prolactin levels completed three normal pregnancies within 3 years of treatment. Six patients (4.3%) with a median tumor volume of 8 cm(3) developed radiation-induced injury at a median of 36 months after GKRS. Five of these patients also underwent external beam radiotherapy and received a median dose of 52.2 Gy in 30 fractions. Quantitative analysis revealed that the radiation dose to critical structures (optic apparatus and pons) is correlated with their distance from tumor margins. Underdosed tumor volume, tumor volume, and total treated volume are correlated with treatment outcomes.

CONCLUSION

GKRS is a safe and effective treatment for selected patients with benign cavernous sinus tumors and is an important adjunct for treating postoperative tumor residual and/or recurrent tumor. Continued analysis of treated patients over an extended time is needed to evaluate long-term disease control and potential late GKRS complications.

Stereotactic radiotherapy for treatment of cavernous sinus meningiomas

PURPOSE

To assess the safety and efficacy of stereotactic radiotherapy (SRT) using a linear accelerator equipped with a micromultileaf collimator for cavernous sinus meningiomas.

METHODS AND MATERIALS

Forty-five patients with benign cavernous sinus meningiomas were treated with SRT between November 1997 and April 2002. Sixteen patients received definitive treatment on the basis of imaging characteristics of the cavernous sinus tumor. Twenty-nine patients received SRT either as immediate adjuvant treatment after incomplete resection or at documented recurrence. Treatment planning in all patients included CT-MRI image fusion and beam shaping using a micromultileaf collimator. The primary tumor volume varied from 1.41 to 65.66 cm(3) (median, 14.5 cm(3)). The tumor diameter varied from 1.4 to 7.4 cm (median, 3.8 cm). Tumor compressed the optic chiasm or optic nerve in 30 patients. All tumors were treated with a single isocenter plus a margin of normal parenchyma varying from 1 to 5 mm (median, 2.5 mm). The prescribed dose varied from 4250 to 5400 cGy (median, 5040 cGy). The prescription isodose varied from 87% to 95% (median, 90%). The maximal tumor dose varied from 5000 to 6000 cGy (median, 5600 cGy). The follow-up varied from 12 to 53 months (median, 36 months).

RESULTS

The actuarial 3-year overall and progression-free survival rate was 100% and 97.4%, respectively. One patient (2%) developed local relapsed at 18 months. A partial imaging response occurred in 18% of patients, and the tumor was stable in the remaining 80%. Preexisting neurologic complaints improved in 20% of patients and were stable in the remainder. No patient, tumor, or treatment factors were found to be predictive of imaging or clinical response. Transient acute morbidities included headache responsive to nonnarcotic analgesics in 4 patients, fatigue in 3 patients, and retroorbital pain in 1 patient. No treatment-induced peritumoral edema, cranial neuropathy, endocrine dysfunction, cognitive decline, or second malignancy occurred. One patient had an ipsilateral cerebrovascular accident 6 months after SRT.

CONCLUSION

Stereotactic radiotherapy is both safe and effective for patients with cavernous sinus meningiomas. Field shaping using a micromultileaf collimator allows conformal and homogeneous radiation of cavernous sinus meningiomas that may not be amenable to single-fraction stereotactic radiosurgery because of tumor size or location. Additional clinical experience is necessary to determine the position of SRT among the available innovative fractionated RT options for challenging skull base meningiomas.

Neuropsychological outcome after fractionated stereotactic radiotherapy (FSRT) for base of skull meningiomas: a prospective 1-year follow-up

PURPOSE

The purpose of this study was to evaluate the cognitive outcome after fractionated stereotactic radiotherapy (FSRT) in patients with base of skull meningiomas.

METHODS AND MATERIAL

A total of 40 patients with base of skull meningiomas were neuropsychologically evaluated before, after the first fraction (1.8 Gy), at the end of FSRT (n=37), 6 weeks (n=24), 6 (n=18) and 12 months (n=14) after FSRT. A comprehensive test battery including assessment of general intelligence, attention and memory functions was used. Alternate forms were used and current mood state was controlled.

RESULTS

After the first fraction a transient decline in memory function and simultaneous improvements in attention functions were observed. No cognitive deteriorations were seen during further follow-up, but increases in attention and memory functions were observed. Mood state improved after the first fraction, at the end of radiotherapy and 6 weeks after radiotherapy.

CONCLUSION

The present data support the conclusion that the probability for the development of permanent cognitive dysfunctions appears to be very low after FSRT. The transient memory impairments on day 1 are interpreted as most likely related to an increase of a preexisting peritumoral edema, whereas the significant acute improvements in attention functions are interpreted as practice effects. An analysis of localization specific effects of radiation failed to show clear hemisphere specific cognitive changes.

Long-term Results after Radiosurgery for Benign Intracranial Tumors

BACKGROUND

Stereotactic radiosurgery is the principal therapeutic alternative to resecting benign intracranial tumors. The goals of radiosurgery are the long-term prevention of tumor growth, the maintenance of patient function, and the prevention of new neurological deficits or adverse radiation effects. Evaluation of long-term outcomes more than 10 years after radiosurgery is needed.

METHODS

We evaluated 285 consecutive patients who underwent radiosurgery for benign intracranial tumors between 1987 and 1992. Serial imaging studies were obtained, and clinical evaluations were performed. Our series included 157 patients with vestibular schwannomas, 85 patients with meningiomas, 28 patients with pituitary adenomas, 10 patients with other cranial nerve schwannomas, and 5 patients with craniopharyngiomas. Prior surgical resection had been performed in 44% of these patients, and prior radiotherapy had been administered in 5%. The median follow-up period was 10 years.

RESULTS

Overall, 95% of the 285 patients in this series had imaging-defined local tumor control (63% had tumor regression, and 32% had no further tumor growth). The actuarial tumor control rate at 15 years was 93.7%. In 5% of the patients, delayed tumor growth was identified. Resection was performed after radiosurgery in 13 patients (5%). No patient developed a radiation-induced tumor. Eighty-one percent of the patients were still alive at the time of this analysis. Normal facial nerve function was maintained in 95% of patients who had normal function before undergoing treatment for acoustic neuromas.

CONCLUSION

Stereotactic radiosurgery provided high rates of tumor growth control, often with tumor regression, and low morbidity rates in patients with benign intracranial tumors when evaluated over the long term. This study supports radiosurgery as a reliable alternative to surgical resection for selected patients with benign intracranial tumors.

Radiosurgical treatment of cavernous sinus meningiomas: experience with 122 treated patients

OBJECTIVE

To evaluate the efficacy of gamma knife (GK) radiosurgery, in terms of neurological improvement and tumor growth control (TGC), for a large series of patients with cavernous sinus meningiomas.

METHODS

Between February 1993 and January 2002, 156 patients with cavernous sinus meningiomas (35 male and 121 female patients; mean age, 56.1 yr) were treated with GK radiosurgery in our department. GK radiosurgery was used as a first-choice treatment for 75 of 156 patients and as postoperative adjuvant therapy for 81 of 156 patients (all with Grade I meningiomas). Eligibility criteria for radiosurgery were as follows: symptomatic meningiomas and/or documented tumor progression on magnetic resonance imaging scans, conditions of high operative risk, patient refusal of microsurgery or reoperation, tumor volume of <20 cm(3), and location no less than 2 mm from the optic pathways.

RESULTS

Follow-up data for at least 12 months were available for 122 patients (median follow-up period, 48.9 mo). Clinical conditions were improved or stable for 118 of 122 patients (97%). Neurological recovery was observed for 78.5% of patients treated with GK radiosurgery alone and for 60.5% of patients treated with adjuvant therapy (P < 0.05). Adequate TGC was documented for 119 of 122 tumors (97.5%), with shrinkage/disappearance in 75 of 122 cases (61.5%) and no variation in volume in 44 of 122 cases (36%); the overall actuarial progression-free survival rate at 5 years was 96.5%. Tumor size regression was observed for 80% of patients with follow-up periods of more than 30 months, compared with 43.5% of patients with follow-up periods of less than 30 months (P < 0.0002). Radiosurgical sequelae were transient in 4 of 122 cases (3.0%) and permanent in 1 case (1%).

CONCLUSION

For the follow-up periods in our series (median, >4 yr), GK radiosurgery seems to be both safe (permanent morbidity rate, 1%) and effective (97% neurological improvement/stability, 97.5% overall TGC, and 96.5% actuarial TGC at 5 yr). GK radiosurgery might be considered a first-choice treatment for selected patients with cavernous sinus meningiomas.

Single dose versus fractionated stereotactic radiotherapy for meningiomas

OBJECTIVE

To evaluate the safety and efficacy of stereotactic radiosurgery (SRS) compared to fractionated stereotactic radiation therapy (FSRT) for meningiomas treated over a seven year period.

METHODS AND MATERIALS

Of the 53 patients (15 male and 38 female) with 63 meningiomas, 35 were treated with SRS and the 18 patients with tumors adjacent to critical structures or with large tumors were treated with FSRT. The median doses for the SRS and the FSRT groups were 1400 cGy (500-4500 cGy) and 5400 cGy (4000-6000 cGy) respectively. Median target volumes for SRS and FSRT were 6.8 ml and 8.8 ml respectively. The median follow-up for the SRS and FSRT groups were 38 months (4.1-97 months) and 30.5 months (6.0-63 months) respectively.

RESULTS

The five-year tumor control probability (TC) for benign versus atypical meningiomas were 92.7% vs. 31% (P = .006). The three-year TC were 92.7% vs. 93.3% for SRS vs. FSRT groups respectively (P = .62). For benign meningiomas, the three-year TC were 92.9% vs. 92.3% for the SRS group (29 patients) vs. FSRT group (14 patients) respectively (P = .77). Two patients in the SRS group and one in the FSRT group developed late complications.

CONCLUSION

Preliminary data suggest that SRS is a safe and effective treatment for patients with benign meningiomas. Fractionated stereotactic radiation therapy with conventional fractionation appeared to be an effective and safe treatment alternative for patients not appropriate for SRS. A longer follow-up is required to determine the long-term efficacy and the toxicity of these treatment modalities.

The role of Gamma Knife radiosurgery in the management of cavernous sinus meningiomas

PURPOSE

To evaluate the efficacy of Gamma Knife (GK) radiosurgery in terms of neurologic improvement and tumor growth control (TGC) in a large series of patients with cavernous sinus meningioma (CSM).

METHODS AND MATERIALS

One hundred thirty-eight patients with CSM (28 males, 110 females; mean age: 56.2 years) were treated with GK between February 1993 and February 2001. GK was used as a first-choice treatment in 68/138 patients and as postoperative adjuvant therapy in 70/138. In 32 patients, it was possible to compare the size of the planned treatment volume to tumor volume using the conformity index (CI); optimal CI values were taken to be < or =1.5 (range: 0.94-2.24).

RESULTS

A follow-up (FU) period of at least 12 months was available for 111 patients (median: 48.2 months, range: 12.1-84.5 months). Clinical conditions were improved or stable in 107/111 patients (96.5%). Neurologic recovery was observed in 76% of cases treated by GK alone and in 56.5% of adjuvant treatments (p < 0.03). Adequate TGC was documented in 108/111 tumors (97%), with shrinkage/disappearance in 70/111 (63%) and no variation in volume in 38/111 (34%); the overall actuarial progression-free survival rate at 5 years was 96%. Tumor size regression was observed in 79.5% of patients with FU >30 months, compared with 47.5% of patients with FU <30 months (p < 0.001). One hundred percent TGC was shown in treated patients with a CI < or =1.5 (20/32), compared with 92% TGC in cases with a CI >1.5 (p < 0.15, NS). Radiosurgical sequelae were transient in 4/111 cases (3.5%) and permanent in one case (1%).

CONCLUSIONS

For the FU period of our series (median: >4 years), GK radiosurgery seems to be both safe (permanent morbidity 1%) and effective (96% neurologic improvement/stability, 97% overall TGC, 96% actuarial TGC at 5 years) and might be considered as a first-choice treatment for selected patients with CSM.

Hepatocyte growth factor is associated with poor prognosis of malignant gliomas and is a predictor for recurrence of meningioma

BACKGROUND

Hepatocyte growth factor (HGF) is a cytokine that participates in multiple cell functions; it promotes proliferation, motility, and morphogenesis of epithelial cells. Some malignant tumors, such as breast carcinoma, bronchogenic carcinoma, and multiple myeloma, overexpress it and its receptor. Hepatocyte growth factor is also present in normal astrocytes; therefore, it is important to investigate whether HGF participates in the pathophysiology of malignant gliomas and other brain tumors. Intratumoral concentration of HGF in human intracranial neoplasms was measured and correlated with prognosis, tumor recurrence, vasogenic edema, cell proliferation index, and vascular density.

METHODS

Hepatocyte growth factor concentration was measured in 62 intracranial tumors, including 16 anaplasic astrocytomas (AA), 16 glioblastoma multiformes (GM), 11 meningiomas, 9 hypophyseal adenomas, 7 oligodendrogliomas, and 3 cordomas, and in 4 samples of nonneoplastic brain tissue. The following parameters were correlated with HGF values: survival and tumor recurrence, cell proliferation index and vascular density as determined by immunohistopathologic analysis, and peritumoral edema as seen by magnetic resonance imaging.

RESULTS

Hepatocyte growth factor concentration (pg/mL) was significantly higher in malignant gliomas (AA and GM) than in adenomas, oligodendrogliomas, and nonneoplastic brain tissue, but it was similar to that of meningiomas. Mean survival of patients with AA was 16.5 +/- 3.6 months and for patients with GM 12.3 +/- 1.3 months. Hepatocyte growth factor concentration was higher in GM than in AA (15,844 +/- 2504 vs. 7499 +/- 1703, P = 0.0375) and was correlated with the cell proliferation index and with poor prognosis. Likewise, mean tumoral concentration of HGF was higher in meningiomas that relapsed than in those without recurrence (22,887 +/- 6489 vs. 2090 +/- 497, P = 0.008).

CONCLUSIONS

Intratumoral concentration of HGF in gliomas is associated with malignancy and poor prognosis. High HGF is also found in meningiomas and is related with long term recurrence. The current findings suggest that the routine measurement of HGF may be used as a predictive factor for planning therapeutic strategies in both malignant gliomas and meningiomas. The potential use of HGF inhibitors or antagonists for therapy of these tumors should be explored.

Anaplastic meningioma: case report

Intracranial meningiomas continue to challenge our best clinical efforts to eliminate them once discovered and deemed appropriate for treatment. Malignant meningiomas constitute 10% to 15% of all meningiomas and limited information exists regarding adjuvant treatment. The external whole brain irradiation is recommended. Traditional chemotherapy has proven ineffective; thus, new chemotherapeutic agents and new methods of delivery should be developed. Immunotherapy may be considered for patients with malignant meningiomas when all others previous treatment have failed. We report a case of anaplastic papillary meningioma. A 67-year-old man presented with partial complex seizures, headache and aggressiveness. A computerized tomography and magnetic resonance image demonstrated a large left temporo-occipital mass with diffuse contrast enhancement and extensive surrounding edema. A left temporo-occipital flap was performed. The tumor and the infiltrated dura were radically removed. Postoperatively, the patient remained neurologically intact. The treatment was complemented by external whole brain radiation.

Efficacy of external fractionated radiation therapy in the treatment of meningiomas: a 20-year experience

BACKGROUND

This is a retrospective analysis of a series of meningiomas treated by radiotherapy.

MATERIALS AND METHODS

From 1978 to 1997, 45 patients with intracranial meningiomas were referred for external fractionated radiotherapy at Centre Alexis Vautrin. All patients were given 50-70Gy to the tumor bed (median: 56Gy), 1.8-2Gy per fraction.

RESULTS

Evaluation was performed in June 1999 using the Kaplan-Meyer actuarial method with a median follow-up of 30 months (range: 1-166), relapse-free survivals (RFSs) were 75% at 5 years and 67% at 8 years; overall survival (OS) was 74% at 5 and 8 years. For the 26 benign histologically documented lesions, RFSs were 95% at 5 years and 81% at 8 years; OS was 85% at 5 and 8 years. One major radiation-induced complication occurred in this series (decline of cognitive function). According to the indication of radiotherapy, we divided the series into four groups: postoperative irradiation after a first subtotal resection (11 patients), 5-year RFS was 90%; after first recurrence (+/-salvage surgery, 14 patients), 73%; after further recurrence (+/-salvage surgery, 11 patients), 67%; as exclusive treatment (nine patients), 80%. Atypical and malignant lesions (n=7) all relapsed before 24 months of follow-up, all patients but one died before 42 months. Age at the time of irradiation (> or =60 vs. <60 years) and radiotherapy dose (> or =60 vs. <60Gy) did not influence local control or OS. Atypical and malignant lesions (WHO grades II and III) meningiomas had a worse outcome than benign lesions (WHO grade I, P<0.01).

CONCLUSIONS

These results compare favorably with previously published data. External fractionated radiotherapy is well tolerated and effective. There is still a debate about the place of radiotherapy in the treatment of meningiomas: after subtotal resection, should radiotherapy be given postoperatively or at the time of progression? Should radiotherapy replace surgery when the risk of postoperative sequellae is high? Prospective randomized trials would be required to address these issues.

Microsurgical removal of a petrous apex meningioma after stereotactic radiation: technical case report

OBJECTIVE AND IMPORTANCE

Stereotactic radiation is increasingly advocated as a primary treatment option for benign cranial base lesions. The clinical course of the patient reported herein raises questions regarding the rationale for initiation of radiotherapy to a petrous apex meningioma before microsurgery.

CLINICAL PRESENTATION

We report a 50-year-old woman who experienced medically refractory trigeminal pain. She was diagnosed with a meningioma around the petrous apex and treated by fractionated stereotactic radiation. After a short period of alleviation accompanied by hypesthesia, the pain returned in a previously unknown and violent fashion.

INTERVENTION

Complete tumor removal through a retrosigmoid intradural suprameatal approach resulted in immediate and permanent pain cessation.

CONCLUSION

Radiotherapy should be withheld for benign and accessible tumors of the cranial base until the option of radical microsurgical treatment has been explored.

[Role of radiotherapy in the treatment of cerebral meningiomas]

Cerebral meningiomas account for 15-20% of all cerebral tumours. Although seldom malignant, they frequently recur in spite of complete surgery, which remains the cornerstone of the treatment. In order to decrease the probability of local recurrence, radiotherapy has often been recommended in atypical or malignant meningioma as well as in benign meningioma which was incompletely resected. However, this treatment never was the subject of prospective studies, randomized or not. The purpose of this review of the literature was to give a progress report on the results of different published series in the field of methodology as well as in the techniques of radiotherapy. Proposals for a therapeutic choice are made according to this analysis. For grade I or grade II-III meningiomas, limits of gross tumor volume (GTV) include the tumour in place or the residual tumour after surgery; clinical target volume (CTV) limits include gross tumour volume before surgery with a GTV-CTV distance of 1 and 2 cm respectively. Delivered doses are 55 Gy into CTV and 55-60 Gy and 70 Gy into GTV for grade I and grade II-III meningiomas respectively.

Long-term tumor control and functional outcome in patients with cavernous sinus meningiomas treated by radiotherapy with or without previous surgery: is there an alternative to aggressive tumor removal?

OBJECTIVE

We report the long-term follow-up of 31 patients with cavernous sinus meningiomas who were treated either with surgery and radiotherapy (RT) or with RT alone. This retrospective review was undertaken to compare long-term efficacy and morbidity of RT with or without previous surgery versus complete, aggressive surgical removal.

METHODS

Between 1980 and 1997, we performed a retrospective study of 31 patients harboring cavernous sinus meningiomas. The patient group comprised 25 women and 6 men. Patients were divided into two therapeutic categories: patients treated with surgery and RT (Group I, 17 patients) and patients treated with RT alone (Group II, 14 patients). Twenty-five patients (14 in Group I and 11 in Group II) were treated for primary tumors, and 6 patients (3 in Group I and 3 in Group II) were treated for recurrent disease. All three patients who were treated by RT alone at the time of recurrent disease had had previous surgery as initial treatment. Tumor control, treatment morbidity, and functional outcomes were evaluated for all patients. Twenty-eight patients were alive at the time of analysis, with a median follow-up period of 6.1 years.

RESULTS

The progression-free survival rate was 92.8% at 10-year follow-up. Only two patients exhibited tumor progression after initial treatment. One of the patients who experienced tumor regrowth 4 years after surgery and RT benefited from additional conventional external beam radiation, and this patient exhibited no evidence of tumor progression at the last follow-up examination 6 years later. Two patients experienced cranial nerve impairment after surgery, and no patients developed late radiation toxicity. Follow-up status as measured by the Karnofsky Performance Scale deteriorated in 7% of patients and was the same or improved in 93% of patients.

CONCLUSION

The results of combined surgery and RT or RT alone indicated a high rate of tumor control and a low risk of complications. Complete aggressive surgical removal of cavernous sinus meningiomas is associated with an increased incidence of morbidity and mortality and does not demonstrate a better rate of tumor control. Conventional external beam radiation seems to be an efficient and safe initial or adjuvant treatment of these lesions, and these findings should serve as a basis for evaluating new alternatives such as radiosurgery or stereotactic RT.