Radiosurgery for malignant meningioma: results in 22 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.

Gamma knife surgery for atypical meningiomas

Object. Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM.

Methods. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21–67 months).

Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery.

Conclusions. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.

Major venous sinus resection in the surgical treatment of recurrent aggressive dural based tumors

BACKGROUND

Despite gross total resection, aggressive dural based tumors invading major venous sinuses have high recurrence rates with poor long-term survivability. Options for aggressive surgical management of dural sinus invasion may be limited by the inherently high risk of morbidity and mortality.

METHODS

Between July 1996 and July 2002, 5 cases of recurrent aggressive dural based tumors were operated on. Gross total resection had been previously performed in 4 cases, and near total resection in 1 case. Tumor pathology included 2 malignant meningiomas, 1 hemangiopericytoma, 1 atypical meningioma, and 1 benign meningioma with atypical features. All tumors recurred within 3 to 47 months and occluded a major venous sinus (four superior sagittal and one dominant right transverse sinus). Gross total resection of tumor and involved venous sinus was accomplished in each case.

RESULTS

Three patients had no signs of clinical or radiographic recurrence at 10, 18, and 53 months of follow up. One patient who developed a fatal pulmonary embolism 10 months postoperatively had evidence of tumor progression on autopsy. One patient had tumor recurrence at 10 months, but is alive at 38 months and receiving adjunctive therapy.

CONCLUSION

For aggressive dural based tumors that recur with invasion of a major venous sinus, radical resection of tumor and occluded sinus can be performed safely and may improve long-term survival.

Proposed Treatment Strategy for Cavernous Sinus Meningiomas: A Prospective Study

OBJECTIVE:

To establish a safe and effective treatment strategy for cavernous sinus (CS) meningiomas, we prospectively analyzed the outcome of a treatment protocol combining surgery and radiosurgery during the past 7 years.

METHODS:

Tumors confined to the CS and distant from the optic apparatus and the brainstem were treated with radiosurgery alone. Tumors attached to or compressing the optic apparatus and brainstem and that were larger than 3 cm in mean diameter, extended into the multiple cranial fossae, and were suspected of being malignant were treated with combined nonradical microsurgery and radiosurgery.

RESULTS:

In accordance with this treatment protocol, 40 patients aged 26 to 72 years (median, 51 yr) with primary (n = 27) or recurrent (n = 13) CS meningiomas (volume range, 0.9–39.3 cm3; median volume, 5.4 cm3) were treated with combined surgery and radiosurgery (n = 23) or radiosurgery alone (n = 17). During radiosurgery, 12 to 18 Gy (median, 16 Gy) was delivered to the tumor margin. The follow-up period ranged from 14 to 79 months (median, 47 mo). The actuarial tumor control rate was 94.1% at 5 years. The improvement of cranial nerve function was significantly frequent in patients with primary CS meningiomas (P&lt; 0.05). Permanent cranial nerve dysfunction was significantly frequent in patients with tumors compressing the brainstem or smaller than 10 cm3 (P&lt; 0.05). All 36 patients with a pretreatment Karnofsky Performance Scale score of 90 or more maintained the same range after treatment.

CONCLUSION:

Proper combination of microsurgery and radiosurgery for CS meningiomas provides excellent growth control with favorable functional state. Outcomes were better when this protocol was adopted at the initial diagnosis for patients with smaller tumors that did not compress the brainstem.

BOLD MRI response to hypercapnic hyperoxia in patients with meningiomas: correlation with Gadolinium-DTPA uptake rate

Because meningiomas tend to recur after (partial) surgical resection, radiotherapy is increasingly being applied for the treatment of these tumors. Radiation dose levels are limited, however, to avoid radiation damage to the surrounding normal tissue. The radiosensitivity of tumors can be improved by increasing tumor oxygen levels. The aim of this study was to investigate if breathing a hyperoxic hypercapnic gas mixture could improve the oxygenation of meningiomas. Blood oxygen level-dependent magnetic resonance imaging and dynamic Gadolinium (Gd)-DTPA contrast-enhanced MRI were used to assess changes in tumor blood oxygenation and vascularity, respectively. Ten meningioma patients were each studied twice; without and with breathing a gas mixture consisting of 2% CO(2) and 98% O(2). Values of T(2)* and the Gd-DTPA uptake rate k(ep) were calculated under both conditions. In six tumors a significant increase in the value of T(2)* in the tumor was found, suggesting an improved tumor blood oxygenation, which exceeded the effect in normal brain tissue. Contrarily, two tumors showed a significant T(2)* decrease. The change in T(2)* was found to correlate with both k(ep) and with the change in k(ep). The presence of both vascular effects and oxygenation effects and the heterogeneous response to hypercapnic hyperoxia necessitates individual assessment of the effects of breathing a hyperoxic hypercapnic gas mixture on meningiomas. Thus, the current MRI protocol may assist in radiation treatment selection for patients with meningiomas.

Meningiomas: Updating Basic Science, Management, and Outcome

BACKGROUND

Meningiomas are biologically complex and clinically and surgically challenging. These features, combined with the rewarding potential for cure, make them of great interest to neurologists, neurosurgeons, and neuroscientists alike.

REVIEW SUMMARY

Initially, we review the clinical context of meningiomas, particularly recent changes in histopathological classification, diagnosis, and neuroimaging. Secondly, the underlying basic science as it has evolved over the last decades is summarized. The status of areas recently of intense interest, such as steroid hormone receptors and oncogenic viruses is described. Additionally, emerging areas of great promise, such as cytogenetics and molecular biology are presented. Lastly, we describe recent advances in management. In particular, skull-base surgery, image-guided surgery, and advances in radiotherapy are emphasized. The possible impact of basic research on management and outcome is also outlined.

CONCLUSIONS

Although usually benign and amenable to cure, meningiomas still present significant diagnostic and treatment challenges. Advances in basic science, surgery, and adjuvant therapy are widening the potential for safe, effective, evidence-based management leading to even better outcomes

Surgical resection and permanent brachytherapy for recurrent atypical and malignant meningioma

OBJECTIVE

Recurrent atypical and malignant meningiomas are difficult to treat successfully. Chemotherapy to date has been unsuccessful, and radiosurgery is limited to smaller tumors. Reoperation alone provides limited tumor control and limited prolonged survival. The addition of brachytherapy at the time of operation is an option. Here, we report the results of our series of patients with recurrent malignant meningioma treated with resection and brachytherapy with permanent low-dose (125)I.

METHODS

The charts of patients in our database with recurrent atypical and malignant meningiomas treated by surgical resection and permanent (125)I brachytherapy at the University of California, San Francisco, between 1988 and 2002 were selected for this study. Calculations of disease-free survival and overall survival curves were made by the Kaplan-Meier actuarial method. Univariate analysis between Kaplan-Meier curves was based on the log-rank statistic, with a significance level set at a value of P </= 0.05.

RESULTS

Seventeen patients had recurrent malignant meningioma, and four had recurrent atypical meningioma. The median number of sources implanted after surgical resection was 30 (range, 4-112 sources), with a median total activity of 20 mCi (range, 3.3-85.9 mCi). The median time to progression after brachytherapy was 11.6 months for patients with malignant meningioma and 10.4 months for the combined group. There was a trend toward longer disease-free survival time in patients after gross total resection versus subtotal resection and in patients with tumors located at the convexity and parasagittally versus at the cranial base. These differences did not reach statistical significance. The median overall survival after diagnosis was 9.4 years for patients with atypical meningioma, 6.6 years for those with malignant meningioma, and 8.0 years for all patients combined. Survival from the time of resection and implantation of (125)I was 1.6 years for patients with atypical meningioma, 2.4 years for patients with malignant meningioma, and 2.4 years for the combined group. Thirty-three percent of patients had complications requiring surgical intervention. Radiation necrosis occurred in 27% of patients; 13% underwent surgery for radiation necrosis. In addition, 27% had a wound breakdown and required surgical intervention.

CONCLUSION

The options for patients with recurrent atypical or malignant meningiomas are limited. Our results suggest that for tumors not suitable for radiosurgery, resection followed by permanent brachytherapy should be considered as a potential salvage treatment. However, this approach results in a relatively high complication rate in these heavily treated patients and requires meticulous surgical technique and medical therapies to assist with wound healing after surgery.

The combination of mitotic and Ki-67 indices as a useful method for predicting short-term recurrence of meningiomas

BACKGROUND

The most relevant factor in the progression-free survival (PFS) of patients with meningiomas is the malignant grade. However, using only the current World Health Organization (WHO) definition that does not consider precise quantitative indicators, an unequivocal diagnosis of the malignant grade is difficult. In our retrospective study of the PFS of meningioma patients, we focused on mitoses and the Ki-67 staining index of tumor specimens obtained at the initial surgery.

METHODS AND RESULTS

A total of 349 patients with intracranial meningioma, operated between 1978 and 2000, were followed for a mean of 7 years. According to the mitotic index (MI), we classified them into 3 groups. In Group A (n = 326), slide-mounted tumor samples exhibited no mitoses; in Group B (n = 15) there were fewer than 4 mitoses, and in Group C (n = 8) 4 or more mitoses were seen per 10 high-power fields (HPF). The estimated 5-year PFS rates in Groups A, B, and C were 93%, 10%, and 13% respectively. The mean PFS for Group A was 148 months; in Groups B and C the median PFS was 43 and 16 months, respectively. A Ki-67 staining index (SI) of less than 1% corresponded with no mitosis, while an SI exceeding 5% was indicative of the presence of mitoses.

CONCLUSION

In meningioma patients, no mitoses and/or a Ki-67 SI <1% signals a favorable outcome. An SI >5% or the presence of mitoses, even fewer than 4 in 10 HPF, is suggestive of a short PFS irrespective of other pathologic features. We suggest that in combination, assay of the Ki-67 SI and the MI represents a reliable, quantitative tool for predicting PFS in meningioma patients.

The effect of radiosurgery during management of aggressive meningiomas

BACKGROUND

Aggressive (atypical or malignant) meningiomas are difficult tumors to manage. We review the local control and survival rates of patients with aggressive meningiomas after multi-modality therapy that included stereotactic radiosurgery (SRS).

METHODS

Thirty patients had SRS for treatment of malignant (n = 12) or atypical (n = 18) meningiomas. There were 17 (57%) males and 13 (43%) females with an average age of 58 years. The mean number of prior surgical resections was two. The median imaging follow-up was 2.3 (0.1-11.4) years; median clinical follow-up was 3.8 (0.25-11.5) years.

RESULTS

After SRS, the overall median time until progression of neurologic signs was 48.0 (+/-6.51) months. Median time to neurologic progression was significantly worse for patients treated late after recurrence versus early after craniotomy. Atypical meningiomas had 5- and 10-year overall actuarial survival rates of 59% (+/-13), while malignant meningiomas had 5- and 10-year overall actuarial survival rates of 59% (+/-16) and 0%. These curves were not significantly different from one another. Atypical meningiomas had a 5-year progression-free survival (PFS) of 83% (+/-7%), while malignant meningiomas had a 5-year PFS of 72% (+/-10) (p = 0.018). On multivariate analysis, early SRS and smaller tumor volumes were associated with better PFS, while younger age was associated with better survival. One patient had an adverse radiation effect after SRS.

CONCLUSIONS

Stereotactic radiosurgery is an important adjuvant management strategy for residual tumors identified early after craniotomy and partial resection. Aggressive use of early boost radiosurgery following craniotomy and radiation therapy is recommended for patients with malignant meningiomas.

Malignant meningioma of the lateral ventricle

This 65-year-old man presented with a very rare malignant meningioma in the trigonum of the right lateral ventricle. Neurological examination showed bilateral papilledema. Magnetic resonance imaging revealed a solid, enhancing tumor in the right trigonum with a hypointense cystic component located in the center of the tumor. The lesion was totally resected via a superior parietooccipital transcortical approach. Histological examination showed an anaplastic (malignant) meningioma with architectural disarray, high mitotic activity (20/10 hpf), necrosis, and cytological atypism. As in our case, heterogeneous signal, due to necrotic tissue and frequently demonstrated on both T1- and T2-weighted sequences, is suggestive of an aggressive type of meningioma.

Stereotactic radiosurgery for intracranial meningiomas: indications and results

Object

Stereotactic radiosurgery (SRS) has become an important treatment option for patients with intracranial meningiomas. The author reviews the 12-year experience at a single institution and discusses the relative strengths and weakness of this management approach.

Methods

Between January 1990 and December 2002, 330 patients (with 356 tumors) underwent radiosurgery for intracranial meningiomas. One hundred thirty-eight patients (42%) harbored recurrent/residual tumors after having already undergone resection; 192 patients (58%) underwent radiosurgery as primary treatment. The majority of patients (70%) harbored skull base tumors. The median tumor volume was 7.3 cm3 (range 0.5–50.5 cm3). The median tumor margin dose was 16 Gy (range 12–20 Gy). In 278 patients with 297 lesions the mean clinical and imaging follow-up period was 43 months (range 2–138 months). Two hundred seventy-eight tumors (94%) remained stable or decreased in size, and 19 tumors progressed in size. Factors associated with progression were tumor histological type and prior surgery. Treatment-related complications occurred in 8% of the patients and included cranial neuropathies, symptomatic edema, cyst formation, and stenosis of the internal carotid artery. In three patients (1%) tumor dedifferentiation was noted after SRS.

Conclusions

Radiosurgical treatment of meningioma is safe and it has become the primary treatment for patients with small skull base tumors. Further study is needed to determine the long-term tumor control rates after such treatment, especially for patients treated with doses of 14 Gy or less.

Stereotactic radiosurgery provides equivalent tumor control to Simpson Grade 1 resection for patients with small- to medium-size meningiomas

PURPOSE

To compare tumor control rates after surgical resection or stereotactic radiosurgery for patients with small- to medium-size intracranial meningiomas.

MATERIALS AND METHODS

Between 1990 and 1997, 198 adult meningioma patients treated at our center underwent either surgical resection (n = 136) or radiosurgery (n = 62) as primary management for benign meningiomas <35 mm in average diameter. Tumor recurrence or progression rates were calculated by the Kaplan-Meier method according to an independent radiographic review. The mean follow-up was 64 months.

RESULTS

The tumor resections were Simpson Grade 1 in 57 (42%), Grade 2 in 57 (42%), and Grade 3-4 in 22 (16%). The mean margin and maximal radiation dose at radiosurgery was 17.7 Gy and 34.9 Gy, respectively. Tumor recurrence/progression was more frequent in the surgical resection group (12%) than in the radiosurgical group (2%; p = 0.04). No statistically significant difference was detected in the 3- and 7-year actuarial progression-free survival (PFS) rate between patients with Simpson Grade 1 resections (100% and 96%, respectively) and patients who underwent radiosurgery (100% and 95%, respectively; p = 0.94). Radiosurgery provided a higher PFS rate compared with patients with Simpson Grade 2 (3- and 7-year PFS rate, 91% and 82%, respectively; p <0.05) and Grade 3-4 (3- and 7-year PFS rate, 68% and 34%, respectively; p <0.001) resections. Subsequent tumor treatments were more common after surgical resection (15% vs. 3%, p = 0.02). Complications occurred in 10% of patients after radiosurgery compared with 22% of patients after surgical resection (p = 0.06).

CONCLUSIONS

The PFS rate after radiosurgery was equivalent to that after resection of a Simpson Grade 1 tumor and was superior to Grade 2 and 3-4 resections in our study. If long-term follow-up confirms the high tumor control rate and low morbidity of radiosurgery, this technique will likely become the preferred treatment for most patients with small- to moderate-size meningiomas without symptomatic mass effect.

[Intracerebral radiotherapy under stereotaxic conditions]

Stereotactic radiosurgery is used for treating several brain diseases. Radiosurgery is a non-invasive alternative to surgery for brain metastases, and randomized trials are on going to assess the role of radiosurgery. Radiosurgery has been advocated for patients with small benign meningioma or with vestibular schwannoma, but there is no proof of efficacy and safety of radiosurgery in comparison with other treatments. Radiosurgery can obliterate 80-90% of small arteriovenous malformations, but no information exists on the survival of treated compared with untreated patients. The limited information available suggests that radiosurgery should be fully evaluated in well-designed prospective studies.

Radiosurgery for treatment of recurrent intracranial hemangiopericytomas

OBJECTIVE

Hemangiopericytomas are highly aggressive meningeal tumors with tendencies for recurrence and metastasis. The purpose of this retrospective, single-institution review was to evaluate the efficacy and role of stereotactic radiosurgery in the management of recurrent hemangiopericytomas.

METHODS

We reviewed data for patients who underwent stereotactic radiosurgery at the University of Pittsburgh between 1987 and 2001. Fourteen patients underwent radiosurgery for 15 discrete tumors. Prior treatments included transsphenoidal resection (n = 1), craniotomy and resection (n = 27), embolization (n = 1), and conventional radiotherapy (n = 7). Clinical and radiological responses were evaluated. Follow-up periods varied from 5 to 76 months (mean, 31.3 mo; median, 21 mo). The mean radiation dose to the tumor margin was 15 Gy.

RESULTS

Seventy-nine percent of patients (11 of 14 patients) with recurrent hemangiopericytomas demonstrated local tumor control after radiosurgery. Twelve of 15 tumors (i.e., 80%) dramatically decreased in size on follow-up imaging scans. Regional intracranial recurrences were retreated with radiosurgery for two patients (i.e., 15%); neither of those two patients experienced long-term tumor control. Local recurrences occurred 12 to 75 months (median, 21 mo) after radiosurgery. Local tumor control and survival rates at 5 years after radiosurgery were 76 and 100%, respectively (Kaplan-Meier method). We could not correlate prior irradiation or tumor size with tumor control. Twenty-nine percent of the patients (4 of 14 patients) developed remote metastases. Radiosurgery did not seem to offer protection against the development of intra- or extracranial metastases.

CONCLUSION

Gamma knife radiosurgery provided local tumor control for 80% of recurrent hemangiopericytomas. When residual tumor is identified after resection or radiotherapy, early radiosurgery should be considered as a feasible treatment modality. Despite local tumor control, patients are still at risk for distant metastasis. Diligent clinical and radiological follow-up monitoring is necessary.

Meningioma radiosurgery: tumor control, outcomes, and complications among 190 consecutive patients

OBJECTIVE

To determine local control (LC) and complication rates for patients with intracranial meningiomas who underwent radiosurgery.

METHODS

One hundred ninety consecutive patients with 206 meningiomas underwent radiosurgery between 1990 and 1998. One hundred forty-seven tumors (77%) involved the cranial base. The median age at the time of radiosurgery was 58 years (range, 20-90 yr). There were 126 female patients (66%). One hundred twelve patients (59%) had undergone one or more previous operations (median, 1; range, 1-5). Twenty-two patients (12%) had either atypical (n = 13) or malignant (n = 9) tumors. The median prescription isodose volume was 8.2 cm(3) (range, 0.5-50.5 cm(3)), and the median tumor margin dose was 16 Gy (range, 12-36 Gy). The median imaging and clinical follow-up periods were 40 and 47 months, respectively.

RESULTS

Overall survival rates for the entire cohort at 5 and 7 years were 82 and 82%, respectively; cause-specific survival rates at 5 and 7 years were 94 and 92%, respectively. The cause-specific survival rates at 5 years for patients with benign, atypical, and malignant tumors were 100, 76, and 0%, respectively (P < 0.0001). The 5-year LC rate was 89%, with 114 tumors (56%) decreasing in size. LC rates were correlated with tumor histological features (P < 0.0001); patients with benign tumors exhibited a 5-year LC rate of 93%, compared with 68 and 0% for patients with atypical or malignant meningiomas, respectively. No correlation was observed between radiation dose and LC rate. Twenty-four patients (13%) experienced treatment-related complications, including cranial nerve deficits (8%), symptomatic parenchymal changes (3%), internal carotid artery stenosis (1%), and symptomatic cyst formation (1%). Only six patients (3%) exhibited decreases in functional status that were directly related to radiosurgery. Tumor volume, tumor margin dose, or previous radiotherapy was not associated with the development of radiation-related complications.

CONCLUSION

Radiosurgery is an effective management strategy for many patients with meningiomas. Patients with atypical or malignant tumors exhibit high recurrence rates despite the use of radiosurgery, and these patients continue to exhibit worse cause-specific survival rates despite aggressive treatment, including surgery, external-beam radiotherapy, and radiosurgery. Further study is needed to determine the tumor control and complication rates 10 years or more after meningioma radiosurgery.

[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.