Atypical and malignant meningioma: outcome and prognostic factors in 68 irradiated patients.

Meningiomas account for up to 20 % of all primary intracranial neoplasms; although the majority of these have a benign course, as many as 5-10 % can display more aggressive behavior and a higher incidence of disease progression. The benefit of immediate adjuvant radiotherapy is still being debated for atypical and malignant meningiomas. This study aimed to retrospectively assess prognostic factors and outcome in 68 patients with atypical and malignant meningiomas. Sixty-eight meningioma patients were treated with radiotherapy after initial resection or for recurrence, between January 1993 and December 2011. Surgery was macroscopically complete in 80 % of the patients; histology was atypical and malignant in 51 patients and 17 patients, respectively. Mean dose of radiotherapy was 54.6 Gy. Fifty-six percent of all patients received radiotherapy after surgical resection, 26 % at the first relapse, and 18 % at the second relapse. Median follow-up was 6.7 years, (range 1.5-19.9 years). The 5- and 10-year actuarial overall survival (OS) rates were 74.1 and 45.6 %, respectively. At univariate analysis age >60 years, radiotherapy dose >52 Gy showed statistical significance, (p = 0.04 and p = 0.03, respectively). At the multivariate analysis radiotherapy dose >52 Gy maintained the statistical significance, (p = 0.037). OS of patients treated with radiotherapy at diagnosis was longer than the survival of patients treated with salvage radiotherapy; however this difference did not reach statistical significance when tested for the entire series or for the subgroups of grade 2 and grade 3 patients. The 5- and 10-year disease-free survival (DFS) rates were 76.5 and 69.5 %, respectively, and were significantly influenced by size >5 cm (p = 0.04) and grading (p = 0.003) on univariate analysis. At multivariate analysis, size and grading both remained significant prognostic factors, p = 0.044 and p = 0.0006, respectively. Grade ≤ 2 acute side effects were seen during radiotherapy treatment in 16 % of the patients, with no ≥ grade 3 acute toxicity, based on the Common Terminology Criteria for Adverse Events. In this mono-institutional retrospective study, age and radiotherapy dose were associated with a longer OS, while preoperative size and grading of the tumor influenced DFS. Although there were some advantages in terms of OS for patients treated with postoperative radiotherapy, the benefit did not reach the significance. Multicenter prospective studies are necessary to clarify the management and the correct timing of radiotherapy in such a rare disease.