Judicious resection and/or radiosurgery for parasagittal meningiomas: outcomes from a multicenter review. Gamma Knife Meningioma Study Group.

Kondziolka D, Flickinger JC, Perez B.   Neurosurgery 1998 Sep;43(3):405-13

Department of Neurological Surgery, University of Pittsburgh, Pennsylvania, USA.

Parasagittal meningiomas, especially when associated with the middle or posterior third of the superior sagittal sinus, pose difficult management challenges. Initial surgical excision is associated with high morbidity and frequent tumor recurrence after subtotal resection. Neurological deficits are cumulative when multiple resections are required. No consistent management approach exists for patients with such tumors. In addition to observation, management options include resection, stereotactic radiosurgery, or fractionated radiation therapy used alone or in combination. Sixteen centers where resection, gamma knife radiosurgery, and/or radiation therapy were available provided management data on 203 patients with histologically benign meningiomas from the time of initial diagnosis through follow-up after radiosurgery. The tumors were located in the anterior superior sagittal sinus in 52 patients, at the middle of the sinus in 91, and at the posterior portion of the sinus in 60. The mean tumor volume at the time of radiosurgery was 10 cc. In patients who underwent radiosurgery as the primary therapy (n = 66), the 5-year actuarial tumor control rate was 93 +/- 4%. No clinical failure (need for additional therapy or worsened neurological function) occurred in patients who had smaller tumors (<7.5 cc) and who had never undergone resection (n = 41). The 5-year control rate for patients with previous surgery was only 60 +/- 10%; the control rate for the radiosurgery-treated volume was 85%. The rate of transient, symptomatic edema after radiosurgery was 16%, was more common with larger tumors, and occurred within 2 years. Of 33 patients who were employed at the time of radiosurgery for whom a minimum of 1 year of follow-up data were available, 30 remained employed (91%). A decrease in functional status after radiosurgery was noted in only 3 of 33 (9%) employed and 7 of 77 (9%) unemployed patients. CONCLUSION: In patients with smaller tumors (<3 cm in diameter) and patent sagittal sinuses, we advocate radiosurgery alone as the first surgical procedure. Patients with larger tumors and those with progressive neurological deficits resulting from brain compression should first undergo resection. Planned second-stage radiosurgery should be performed soon afterward for any residual tumor nodule or neoplastic dural remnant. Multimodality management may enhance long-term tumor control, reduce the need for multiple resections, and maintain the functional status of the patient.

The effectiveness and factors related to treatment results of gamma knife radiosurgery for meningiomas.

Pan DH, Guo WY, Chang YC, Chung WY, Shiau CY, Wang LW, Wu SM.  Stereotact Funct Neurosurg 1998 Oct;70 Suppl 1:19-32

Division of Functional Neurosurgery, Neurological Institute, Taipei, Taiwan.

A retrospective analysis was conducted on 80 patients with intracranial mengiomas treated with Gamma Knife radiosurgery between 1993 and 1996.  Mean follow-up duration was 21 months (range 6-45 months). 63 meningiomas were at the skull base and 17 were distal from the skull base. Tumor volumes <5 ml (n=38), 5-10 ml (n=21), 10-15 ml (n=14), 15-20 ml (n=7). The patients were divided into 3 groups according to the radiation dose. The groups were high-dose (peripheral dose 17-20 Gy, n=19), medium-dose (15-16 Gy, n=33) and low-dose (12-14 Gy, n=28) groups. The volume measurement at the latest follow-up showed 74% (59/80) meningiomas decreased in volume, 17% (14/80) had no tumor enlargement and 9% (7/80) had increased in volume. The increased volume was found more frequently in the patients with a short (6-12 months) follow-up period. In this series, the tumors had 32&percnt reduction in average tumor volume at 3 years after radiosurgery. At the range of 12-20 Gy peripheral dose (PD), radiosurgery was effective to reduce tumor volume 0.7% per month (p<0.05). However, higher doses had no significant difference on tumor volume reduction (p>0.05). On the other hand, high-dose (PD>17 Gy) treatment was associated with a higher risk of temporary tumor swelling and the development of adverse radiation effects (AREs). The AREs detected on MR images occurred in (25/80) 31% patients. Only 6/25 AREs were symptomatic and 2 had neurological sequelae. Peripheral doses, tumor volumes and their locations had significant impacts on the ARE (p<0. 05). In conclusion, a peripheral dose of 15-16 Gy may be adequate for meningiomas with small volumes (<5 ml). In larger tumors (>10 ml) a lower PD is preferred (12-14 Gy). To avoid initial tumor swelling and ARE, high-dose irradiation (PD>17 Gy) is not recommended for meningiomas larger than 5 ml.

Gamma Knife treatment of 100 consecutive meningiomas.

Hudgins WR, Barker JL, Schwartz DE, Nichols TD.  Stereotact Funct Neurosurg 1996;66 Suppl 1:121-8

Department of Neurosurgery, Presbyterian Hospital of Dallas, Tex., USA.

Clinical and imaging results of Gamma Knife treatment of 100 consecutive patients with intracranial meningiomas are reported. Only 1 patient refused follow-up imaging and her symptoms remain improved after 1 year. Mean values for the patient and treatment parameters were age 61 years, duration of symptoms 3.6 years, time since diagnosis 3 years, average tumor diameter 2.4 cm, surface radiation dose 15 Gy and number of isocenters 5. Clinical outcomes revealed that 6 were improved, 75 were unchanged and 17 had deteriorated. Of the latter, 8 were operated, 4 were treated medically and 5 died. Imaging follow-up showed no growth in 87 patients. The size of tumors treated ranged from 0.66 to 6.8 cm average diameter. In the 77 patients with tumors with an average diameter of 3 cm or less, only 2 (3%) showed further growth, and none died of tumor-related causes.

Stereotactic radiosurgery for tentorial meningiomas.

Muthukumar N, Kondziolka D, Lunsford LD, Flickinger JC.   Acta Neurochir (Wien) 1998;140(4):315-20

Department of Neurological Surgery, University of Pittsburgh School of Medicine, PA, USA.

Radical microsurgical resection is the procedure of choice for tentorial meningiomas. Despite advances in microsurgery, tentorial meningiomas continue to challenge surgeons and patients. To evaluate the response of tentorial meningiomas, we evaluated 41 patients who had Gamma knife stereotactic radiosurgery during a 9 year period. Patient age varied from 32 to 79 years. Headache, trigeminal neuralgia, or facial paraesthesia were the most common presenting symptoms. Sensory deficits in the distribution of the trigeminal nerve were the most common finding. Eighteen patients (44%) had undergone between 1 and 5 (mean, 1.9) resections prior to radiosurgery; 23 had tumors diagnosed by neuroimaging. The average tumor diameter in this series was 20 mm. The maximum tumor dose varied from 24 to 40 Gy (mean, 30.5 Gy), and the tumor margin dose varied from 12 to 20 Gy (mean, 15.3 Gy). During the average follow-up interval of 3 years (range, 1-8 years), 19 patients had clinical improvement, 20 remained stable, and 2 patients deteriorated. Follow-up imaging showed a reduction in tumor size in 18 patients, no further tumor growth in 22, and an increase in tumor size in one (overall tumor control rate of 98%). Stereotactic radiosurgery using the Gamma Knife was a safe and effective primary or adjuvant treatment for patients with tentorial meningiomas.

Gamma Knife Radiosurgery in Meningiomas of the Posterior Fossa. Experience with 62 Treated Lesions.

Nicolato A, Foroni R, Pellegrino M, Ferraresi P, Alessandrini F, Gerosa M, Bricolo A.    Minim Invasive Neurosurg 2001 Dec;44(4):211-217

Department of Neurosurgery, University Hospital, Verona, Italy.

Abstract. OBJECTIVES: This study was untertaken to assess the role of the gamma knife (GK) in the treatment of meningiomas of the posterior cranial fossa (PCF) and to statistically analyze the predictability of arbitrarily-selected prognostic factors in such treatment. METHODS: From February 1993 to November 1998, 57 patients underwent GK treatment for 62 meningiomas of the PCF (19 M/38 F; average age, 57.5 years, ranging from 25 - 82 years). Tumor sites included: foramen jugular-petrous bone (26/62), petroclival (23/62), cerebellar convexity (6/62), tentorium (6/62), and foramen magnum (1/62). Single lesions were treated in 44/62 cases while meningiomatosis was treated in the remaining 18. Post-operative residual or recurrent tumor was found in 27/62 patients and, in 7/27, histology documented characteristics of biological aggressiveness (GII/III). Indications for radiosurgery included: advanced age, high operative risk, tumor volume < 20 ml, inoperable or refused for additional surgery. The prognostic factors statistically analyzed included: meningiomatosis (yes/no), radiosurgery as primary or adjuvant treatment, GI vs. GII/III histology, and tumor volume ([less-than-or-equal] 5 ml vs. > 5 ml). RESULTS: The observation periods varied from 6 to 64.3 months (median 28.7 months). At the end of the study, 53/57 patients were alive and reported to be in stable or improved neurological condition. The cause of death for the remaining 4 patients included: 2 deaths associated with tumor progression, while 2 died due to causes unrelated to the disease. Neuroradiological evaluation documented the disappearance or reduction of the meningioma mass in 34/62 (55 %) cases, a stable imaging picture in 25/62 (40 %), and a progression only in 3/62 (5 %). To date, there have been no reported cases of post-GK permanent morbidity or mortality. Side effects observed were of a transient nature due to post-radiosurgical edema (6.5 %). With regard to statistical analysis, the only factor to appear to significantly influence efficacy of radiosurgery for tumor growth control (TGC) was the biological nature of the meningioma ([chi](2) = 2.708). The presence of meningiomatosis, SR as a primary or adjuvant treatment nor tumor volume were shown to statistically influence tumor behavior after GK. CONCLUSIONS: The excellent results obtained for TGC with minimal associated side effects suggest that GK is an effective therapeutic tool also for treatment of PCF meningiomas.

Radiosurgery for malignant meningioma: results in 22 patients.

Ojemann SG, Sneed PK, Larson DA, Gutin PH, Berger MS, Verhey L, Smith V, Petti P, Wara W, Park E, McDermott MW.

Department of Neurological Surgery, University of California, San Francisco 94143, USA.   J Neurosurg 2000 Dec;93 Suppl 3:62-7

Twenty-two patients who underwent GKS for malignant meningioma between December 1991 and May 1999 were evaluated. Three patients were treated with GKS as a boost to radiotherapy and 19 for recurrence following radiotherapy. Overall 5-year survival and progression-free survival estimates were 40% and 26%, respectively. Age (p < or = 0.003) and tumor volume (p < or = 0.05) were significant predictors of time to progression and survival in both univariate and multivariate analyses. Five patients (23%) developed radiation necrosis. Significant relationships between complications and treatment variables or patient characteristics could not be established. CONCLUSIONS: Tumor control following GKS is greater in patients with smaller-sized tumors (< 8 cm3) and in younger patients. Gamma knife radiosurgery can be performed to treat malignant meningioma with acceptable toxicity. The efficacy of GKS relative to other therapies for recurrent malignant meningioma as well as the value of GKS as a boost to radiotherapy will require further evaluation.

Preservation of visual fields after peri-sellar gamma-knife radiosurgery.

Ove R, Kelman S, Amin PP, Chin LS.   Int J Cancer 2000 Dec 20;90(6):343-50

Department of Radiation Oncology, University of Maryland Medical System, 22 S. Greene St., Baltimore, Maryland 21201, USA. ove@uabmc.edu

Radiosurgical treatment of pituitary and peri-sellar tumors has become an increasingly utilized modality as an alternative to conventional radiotherapy and surgery. Such radiosurgery results in a relatively high dose of radiation to the optic chiasm. The clinical data establishing safe single-fraction doses to the chiasm is immature, although taken together previous literature suggests a recommended maximal dose of 8 Gy. Optic neuropathy, when it occurs, tends to take place within 2 years of treatment. We evaluated the visual fields of 20 sequential patients that received significant doses to the optic chiasm by Gamma-knife radiosurgery. There were 17 cases of pituitary adenoma and 3 cases of meningioma, and two patients refused follow-up testing. Preoperative visual field and cranial nerve examinations were done prior to radiosurgery and in follow-up, with a median follow-up of 24 months. There were no cases of quantitative visual field deficit induced by treatment. No patients developed symptomatic visual deterioration.

Radiosurgery as alternative treatment for skull base meningiomas.

Pendl G, Eustacchio S, Unger F.    J Clin Neurosci 2001 May;8 Suppl 1:12-4

Department of Neurosurgery, Medical School and University, Graz, Austria.

The effect of radiosurgical treatment of skull base meningiomas in 197 patients with a follow-up of at least 2 years was evaluated. Ninety-two of these patients had combined surgical and radiosurgical treatment, while Gamma Knife Radiosurgery (GKRS) was performed as primary treatment in 105 patients. Follow-up was available in 164 patients with intervals of 25-97 months (median 55 months) after GKRS. The imaging controls revealed decreased tumour size in 84 patients (51%), stable tumour volume in 76 ca ses (47%) and increased tumour size in 4 cases (2%). Neurological examinations showed improved neurological status in 58 cases (35%), stable clinical status in 100 patients (61%) and slight worsening in 6 cases (4%). Due to excellent tumour control rate, good clinical outcome and a low complication rate GKRS represents not only an attractive additional treatment option for basal meningiomas, but may even replace microsurgery in selected cases

Gamma knife radiosurgery for skull base meningiomas.

Pollock BE, Stafford SL, Link MJ.  Neurosurg Clin N Am 2000 Oct;11(4):659-66

Department of Neurological Surgery, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.

Radiosurgery has been proven to be a safe and effective management strategy for skull base meningiomas either primarily or for tumor recurrence or progression after prior microsurgical resection. With its steep radiation falloff, radiosurgery provides long-term tumor growth control without the complications associated with conventional fractionated radiation therapy. Stereotactic MR imaging has allowed better definition of the tumor margin for precise multiisocenter conformal dose planning, and our current radiation dose prescription has decreased the incidence of new cranial nerve deficits after radiosurgery to less than 10%. Tumor growth control after radiosurgery remains greater than 90%; patients with subsequent growth typically have tumor outside the irradiated volume or a histologic diagnosis of atypical or malignant meningioma. Still, longer follow-up is needed to ensure that tumor growth control remains permanent after radiosurgery. For patients with large tumors of the skull base, radiosurgery can be part of a staged approach with microsurgery. Initially, the tumor is debulked without an attempt at resection involving the cranial nerves or basal vessels. Radiosurgery can then be performed for the small remaining tumor volume with little risk of cranial nerve deficits. Such multimodality treatment should result in reduced patient morbidity, with long-term tumor control.

Early complications following gamma knife radiosurgery for intracranial meningiomas.

Singh VP, Kansai S, Vaishya S, Julka PK, Mehta VS.  J Neurosurg 2000 Dec;93 Suppl 3:57-61

Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi.

OBJECT: The purpose of this paper was to assess the early complications, defined as occurring within 1 year, following gamma knife radiosurgery (GKS) for the treatment of intracranial meningiomas. METHODS: Seventy-seven of 306 patients undergoing GKS in the last 2.5 years harbored meningiomas. There were 35 men and 42 women with a mean age of 32.4 years (range 10-80 years). Tumor volume ranged from 0.35 to 28.6 cm3 (mean 7.9 cm3). Gamma knife radiosurgery was the primary therapy in 28 patients and followed surgery in 49 patients. There were 50 basal and 27 nonbasal meningiomas. The most common sites were parasagittal (23 patients) and cerebellopontine angle (14 patients). Ten to 15 Gy was administered to the tumor margins. Clinical and radiological follow up with a mean duration of 122 months was available in 40 patients. Seizures and increased headache were found in five and four patients, respectively. A temporary worsening of hemiparesis was seen in two patients (both with parasagittal tumors). One patient with a cavernous sinus meningioma developed a herpes labialis eruption. Perilesional edema was demonstrated in nine patients and was symptomatic in six. Six (22%) of the 27 patients with nonbasal tumors had edema (all parasagittal) and four patients were symptomatic. Only three (6%) of the 50 basal meningiomas had edema, and only one patient was symptomatic. The occurence of edema did not correlate with tumor volume, margin or maximum dose, or with radiation received by adjacent brain. A reduction in tumor size was seen in seven patients. In one patient a new recurrent lesion developed adjacent to the previously treated tumor. CONCLUSIONS: Although GKS provides good results for selected patients with meningiomas, caution is required in treating patients with parasagittal tumors as the incidence of perilesional edema is considerable.

Management of petroclival meningiomas by stereotactic radiosurgery.

Subach BR, Lunsford LD, Kondziolka D, Maitz AH, Flickinger JC.  Neurosurgery 1998 Mar;42(3):437-43

Department of Neurological Surgery, Center for Image-Guided Neurosurgery, University of Pittsburgh Medical Center, Pennsylvania, USA.

we retrospectively reviewed our experience with 62 patients managed at the University of Pittsburgh during an 8-year period. METHODS: All patients had cranial base meningiomas involving the region between the petrous apex and the upper two-thirds of the clivus. Some tumors extended into the cavernous sinus. Each of 39 patients (63%) had previously undergone one or more attempts at surgical resection. Seven patients (11%) had received fractionated external beam radiation therapy. Using the gamma knife, conformal multiple isocenter radiosurgery was performed with tumor margin doses of 11 to 20 Gy. RESULTS: During the median follow-up period of 37 months, neurological statuses improved in 13 patients (21%), remained stable in 41 patients (66%), and eventually worsened in 8 patients (13%). Tumor volumes decreased in 14 patients (23%), remained stable in 42 patients (68%), and increased in 5 patients (8%). Despite the proximity of these tumors to critical neural and vascular structures, complications resulting from radiosurgery were rare. Five patients (8%) developed new cranial nerve deficits within 24 months of radiosurgery, although none had evidence of tumor progression. These deficits resolved completely in two patients within 6 months of onset. CONCLUSION: Although an even longer follow-up period is desirable, we conclude that stereotactic radiosurgery provides a safe and effective management strategy for petroclival meningiomas, both as a primary procedure and as an adjunct to incomplete resection.

A comparison of single fraction radiosurgery tumor control and toxicity in the treatment of basal and nonbasal meningiomas.

Vermeulen S, Young R, Li F, Meier R, Raisis J, Klein S, Kohler E.  Stereotact Funct Neurosurg 1999;72 Suppl 1:60-6

Swedish Hospital Tumor Institute, Seattle, WA 98104, USA.

Between July 1993 and October 1997, 107 patients with 118 meningiomas were treated with Gamma Knife radiosurgery (GKRS). The most frequent site of tumor origin was the skull base (54%). The mean tumor diameter and volume were 2.5 cm and 9.4 cm3, respectively. The mean dose to the tumor periphery was 17 Gy, prescribed to a mean iso-dose of 47%. At a mean follow-up of 28 months, tumor control for basal and nonbasal meningiomas was 80%. Deteriorating peritumoral edema associated with symptoms was observed in 1 of 49 (2%) skull-base tumors and in 4 of 39 (10%) non-basal tumors, without associated tumor growth. (p=0.l5 and 0.234 respectively, z-test). Stereotactic radiosurgery can achieve acceptable tumor control with low morbidity in the treatment of most meningiomas. However, when the tumor is nonbasal, the potential morbidity from peritumoral edema should be recognized and other treatment options considered, such as adjuvant surgery, partial fractionated irradiation or stereotactic radiotherapy.