Malignant meningioma: an indication for initial aggressive surgery and adjuvant radiotherapy.
Malignant meningiomas constitute a rare subset of meningiomas and display a marked propensity for postsurgical recurrence. This retrospective study evaluates the various parameters which alter the recurrence rate. The records of all malignant meningioma patients treated from 1984 through 1992 were reviewed, and the time to recurrence or current patient status was determined, and the influence of various patient and disease parameters were analyzed. 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. Subtypes included 32 anaplastic meningioma, 11 hemangiopericytoma, 2 meningiosarcoma, and 3 papillary meningioma. Followup ranged from 3 to 144 months, with five patients excluded from analysis. Actuarial disease free/progression free survival (DFS) at 5 years was 39% following total resection versus 0% after subtotal resection (p=0.001). For all totally excised lesions, the 5-yr DFS was improved from 28% for surgery alone to 57% with adjuvant radiotherapy (p=NS). Adjuvant irradiation following initial resection increased the 5-yr DFS rates from 15% to 80% (p=0.002). When administered for recurrent lesions, adjuvant radiotherapy improved the 2-yr DFS from 50% to 89% (p=0.015), but had no impact on 5-yr DFS. Multivariate analysis indicates extent of resection, adjuvant radiotherapy, and recurrence status are independent prognostic factors. 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.