Int J Radiat Oncol Biol Phys 1990 Apr;18(4):755-61

The role of radiotherapy in the management of intracranial meningiomas: the Royal Marsden Hospital experience with 186 patients.

Glaholm. The 10-year actuarial cause-specific survival was 67% for all cases and the actuarial disease-free survival was 61%. Of those who underwent subtotal or partial tumor resection with post-operative radiotherapy the 10-year actuarial cause-specific survival was 77%, and in inoperable patients treated by radiotherapy alone it was 46%. Radiotherapy alone resulted in improvement of neurological performance (Karnofsky) in 12 out of the 32 (38%) patients with inoperable disease. The 10-year survival of patients referred for irradiation following "complete" surgical resection was only 34% owing to the high incidence of adverse histological sub-types in this treatment sub-group. Patients undergoing complete surgical resection for the typical benign non-aggressive meningioma do not require adjuvant irradiation. The results of this study support the role of radiotherapy for treatment of incompletely resected and inoperable meningioma of all 3 histological types (benign, "aggressive benign", malignant).

Int J Radiat Oncol Biol Phys 1988 Aug;15(2):299-304

The meningioma controversy: postoperative radiation therapy.

Taylor. The actuarial local control rates at 10 years for the three treatment groups were as follows: subtotal excision alone, 18%; subtotal excision plus postoperative radiation therapy, 82%; and total excision alone, 77%. The actuarial determinate survival rates at 10 years were 49%, 81%, and 93%, respectively. Postoperative radiation therapy was also effective for patients treated at the time of the first recurrence, with an actuarial local control rate at 10 years after salvage treatment of 30% for patients treated with surgery alone and 89% for patients receiving postoperative radiation therapy at the time of salvage. This analysis suggests that radiation therapy has a significant role in the treatment of subtotally excised and recurrent intracranial meningiomas.

J Neurosurg 1994 Feb;80(2):195-201

Postoperative irradiation for subtotally resected meningiomas. A retrospective analysis of 140 patients treated from 1967 to 1990.

Goldsmith. retrospectively analyzed 140 patients treated at the University of California, San Francisco, from 1967 to 1990 to evaluate the results of radiation therapy (median 5400 cGy) given as an adjuvant to subtotal resection of intracranial meningioma. Of the 140 meningiomas, 117 were benign and 23 were malignant. The overall survival rate at 5 years was 85% for the benign and 58% for the malignant tumor groups ; the 5-year progression-free survival rates were 89% and 48%, respectively. For patients with benign meningioma, the 10-year overall and progression-free survival rates were 77%. The 5-year progression-free survival rate for patients with benign meningioma treated after 1980 (when computerized tomography or magnetic resonance imaging was used for planning therapy) was 98%, as compared with 77% for patients treated before 1980. Morbidity (3.6%) included sudden blindness or cerebral necrosis and death. When total resection of benign meningioma is not feasible, subtotal resection combined with precise treatment planning techniques and adjuvant radiation therapy can achieve results comparable to those of total resection.

J Neurooncol 1992 Jun;13(2):157-64

The role of radiotherapy in the treatment of subtotally resected benign meningiomas.

Miralbell. Progression-free survival for 17 patients irradiated after initial incomplete surgery was 88% at 8 years compared with 48% for similar patients treated by surgery alone . 16 patients incompletely resected at time of first recurrence were irradiated and 78% were progression-free at 8 years while 11% of a similar group treated by surgery alone were progression free (p = 0.001). Long term overall survival was high and similar in both control and study groups. Two patients were irradiated at second recurrence and 1 patient at third recurrence. Twenty-five patients were treated with photons alone and have a median follow-up of 57 months, 6 patients have recurred at doses 45-60 Gy. Eleven patients were treated with combined 10 MV photons and 160 MV protons utilizing 3-D treatment planning. These patients have been followed for a median of 53 months and none have failed to date. Eight of 11 received 54-60.4 Gy and 3/11 greater than 64.48 Gy.

Neurosurgery 1987 Apr;20(4):525-8

Radiation therapy in the treatment of partially resected meningiomas.

Barbaro. we reviewed the records of all patients admitted to the University of California, San Francisco, between 1968 and 1978 who had a diagnosis of intracranial meningioma. The patients were divided into three groups: 51 patients had gross total resection and did not receive radiation therapy, 30 patients had subtotal resection and no radiation therapy, and 54 patients had subtotal resection followed by radiation therapy. The subtotal resection groups were similar in average age, male:female ratio, and tumor location, which allowed a valid comparison of the effects of irradiation. The recurrence rate in the total resection group was 4% (2 of 51 patients). Among patients in the subtotal resection groups, 60% of nonirradiated patients had a recurrence, compared with only 32% of the irradiated patients. The median time to recurrence was significantly longer in the irradiated group than in the nonirradiated group (125 vs. 66 months, P less than 0.05). There was no complication related to irradiation. These results provide convincing evidence that radiation therapy is beneficial in the treatment of partially resected meningiomas.
 
Mayo Clin Proc 1998 Oct;73(10):936-42

Primarily resected meningiomas: outcome and prognostic factors in 581 Mayo Clinic patients, 1978 through 1988.

Stafford. From 1978 through 1988, 581 patients underwent initial resection of a previously untreated primary meningioma at Mayo Clinic Rochester. Gross total resection (GTR) of the meningioma was accomplished in 80% of patients; the other 20% underwent less than GTR. Progression-free survival at 5 and 10 years was 88% and 75%, respectively, in patients who underwent GTR and 61% and 39%, respectively, in those who underwent less than GTR. A trend toward improved progression-free survival was noted after first recurrence when irradiation with or without operation was used in comparison with only surgical treatment (P = 0.058). CONCLUSION: With only operative treatment of meningioma, the 10-year recurrence rate was 25% in patients who had GTR and 61% in those who had less than GTR. These results emphasize the need for long-term follow-up and for consideration of adjuvant radiation therapy. Patients treated at the time of recurrence seem to benefit from radiation therapy with or without surgical resection.

J Neurosurg 1985 Jan;62(1):18-24

Meningioma: analysis of recurrence and progression following neurosurgical resection.

Mirimanoff .The rates of survival, tumor recurrence, and tumor progression were analyzed in 225 patients with meningioma who underwent surgery as the only treatment modality between 1962 and 1980. The absolute 5-, 10-, and 15-year survival rates were 83%, 77%, and 69%, respectively. Following a total resection, the recurrence-free rate at 5, 10, and 15 years was 93%, 80%, and 68%, respectively, at all sites. In contrast, after a subtotal resection, the progression-free rate was only 63%, 45%, and 9% during the same period (p less than 0.0001). The probability of having a second operation following a total excision after 5, 10, and 15 years was 6%, 15%, and 20%, whereas after a subtotal excision the probability was 25%, 44%, and 84%, respectively (p less than 0.0001). Tumor sites associated with a high percentage of total excisions had a low recurrence/progression rate. For example, 96% of convexity meningiomas were removed in toto, and the recurrence/progression rate at 5 years was only 3%. Parasellar meningiomas, with a 57% total excision rate, had a 5-year probability of recurrence/progression of 19%. Only 28% of sphenoid ridge meningiomas a second resection, the probability of a third operation at 5 and 10 years was 42% and 56%, respectively.

Int J Radiat Oncol Biol Phys 1996 Mar 1;34(4):817-22

Radiotherapy for atypical or malignant intracranial meningioma.

Milosevic. The records of the 59 patients who were treated at the Princess Margaret Hospital between 1966 and 1990 with histologically confirmed intracranial atypical or malignant meningiomas were retrospectively reviewed. The median age was 58 years. Twenty-four patients were referred for radiation immediately after diagnosis and the remainder after at least one recurrence. All patients received megavoltage radiation to a median dose of 50 Gy. RESULTS: Disease progressed in 39 patients (66%) after radiation. The 5-year actuarial overall and cause-specific survivals were 28 and 34%, respectively. Age less than 58, treatment after 1975, and a radiation dose of 50 Gy or more were independently associated with higher cause-specific survival by multivariate analysis. CONCLUSIONS: Young age, modern imaging and treatment planning techniques, and a postoperative radiation dose of at least 50 Gy contribute to improved outcome in patients with atypical or malignant meningiomas. We recommend that all patients receive radiotherapy immediately after initial surgery.

J Neurooncol 1998 Apr;37(2):177-88

Malignant meningioma: an indication for initial aggressive surgery and adjuvant radiotherapy.

Dziuk. Thirty-eight patients were treated with 48 malignant meningioma resections performed (28 total and 20 subtotal), 25 at initial presentation and 23 for recurrent disease; 19 patients received postoperative radiotherapy.  Actuarial disease free/progression free survival (DFS) at 5 years was 39% following total resection versus 0% after subtotal resection. For all totally excised lesions, the 5-yr DFS was improved from 28% for surgery alone to 57% with adjuvant radiotherapy. Adjuvant irradiation following initial resection increased the 5-yr DFS rates from 15% to 80%. When administered for recurrent lesions, adjuvant radiotherapy improved the 2-yr DFS from 50% to 89%, but had no impact on 5-yr DFS. Malignant meningiomas display a tendency for post surgical recurrence, with recurrence significantly increased for multicentric and recurrent disease. Complete surgical resection and the administration of adjuvant irradiation following initial resection are crucial to long-term control.

J Neurosurg 1996 May;84(5):733-6

Adjuvant combined modality therapy for malignant meningiomas.

Chamberlain. Malignant meningiomas constitute 10% to 15% of all meningiomas and limited information exists regarding adjuvant treatment of these aggressive primary brain tumors. Fourteen patients (eight men, six women), ranging in age from 28 to 61 years (median 51 years), were prospectively treated for primary malignant meningiomas according to an institutional protocol. All patients underwent surgery (gross-total in four and subtotal resection in 10 patients) followed in 2 to 4 weeks by involved-field radiotherapy (range 59-60 Gy, median dose 60 Gy). Two to 4 weeks after radiotherapy all patients were treated with adjuvant chemotherapy that included cyclophosphamide, adriamycin, and vincristine (CAV). Patients who underwent gross-total resection received three cycles, whereas those with subtotal resection received six cycles of CAV. The median time to tumor progression was 4.6 years (range 2.2-7.1 years) and median survival was 5.3 years (range 2.6-7.6 years). The author concludes that combined modality therapy for the treatment of malignant meningiomas is associated with acceptable toxicity and a modest improvement in survival when compared to patients treated with surgery alone.

Neurosurgery 1998 Mar;42(3):446-53; discussion 453-4

Results of linear accelerator-based radiosurgery for intracranial meningiomas.

Hakim. We reviewed 127 patients with 155 meningiomas treated with stereotactic radiosurgery (SRS) at the study institutions between October 1988 and December 1995.The median tumor volume was 4.1 cc (range, 0.16-51.2 cc), and the median marginal dose was 15 Gy (range, 9-20 Gy). Freedom from progression was observed in 107 patients (84.3%) at a median time of 22.9 months (range, 1.2-79.8 mo). Twenty patients (15.7%) had disease progression (16 marginal [12.6%] and 4 local [3.1%]) at a median time of 19.6 months (range, 4.1-69.3 mo); the median time for freedom from progression for the benign, atypical, and malignant meningiomas was 20.9, 24.4, and 13.9 months, respectively. Actuarial tumor control for the patients with benign meningiomas was 89.3% at 5 years. Six patients (4.7%) had permanent complications attributable to SRS  13 patients died as a result of causes related to the meningiomas (median, 17.5 mo; range, 4.3-37.3 mo). The 5-year survival probability for the entire group of patients was  68.2%,  for patients with benign meningiomas, excluding death resulting from intercurrent disease, the survival probability was 91.0%, . The 4-year survival probability for the patients with atypical and malignant meningiomas was 83.3% and21.5%, respectively. CONCLUSION: Even though complications from SRS are expected more frequently with large tumors near critical structures, SRS is a safe and effective means of treating selected meningiomas.