Long-Term Outcomes of Newly Diagnosed Resected Atypical Meningiomas and the Role of Adjuvant Radiotherapy

Objective The role of adjuvant radiotherapy (ART) in patients with World Health Organization Grade II atypical meningiomas (AMs) remains controversial. Methods We retrospectively reviewed 149 patients with newly diagnosed resected AMs from 2000 to 2012. Gross total resection (GTR) was defined as Simpson Grades I–III and subtotal resection (STR) as Grades IV and V. Kaplan-Meier analyses of local control (LC), progression-free survival (PFS), and overall survival were performed with the log-rank test, and risk factors for progression/recurrence (P/R) were analyzed with multivariate Cox regression. Results Median follow-up was 74.2 months. GTR was achieved in 98 patients and STR in 51 patients. Fifty-three (35%) patients received ART. Overall, 46 patients (31%) experienced P/R with a median time to P/R of 32.4 months. ART was associated with a trend toward improved PFS ( P  = 0.0669) in the GTR subset but significantly improved LC ( P  = 0.0183) and PFS ( P  = 0.0034) in the STR subset. Age, tumor size, and STR were significant risk factors for worse PFS, whereas receiving ART was associated with improved PFS on multivariate analyses. Thirty-nine of the 46 progressive/recurrent patients underwent salvage therapy with only 22 patients experiencing long-term control. Five patients experienced transformation to World Health Organization Grade III malignant meningioma. Conclusions Patients who undergo STR for newly diagnosed AM should receive ART based on improvements in LC and PFS. GTR patients should be considered for ART, but active surveillance is a reasonable management approach with the recognition that progressive/recurrent disease can act aggressively. Prospective, randomized trials are currently underway to evaluate the role of ART.