Adjuvant Radiation Therapy Versus Surveillance Following Surgical Resection of Atypical Meningiomas

Abstract

Background: The optimal timing of adjuvant radiotherapy (RT) in the management of atypical meningiomas remains controversial. We compared the outcomes of atypical meningiomas managed with upfront adjuvant RT versus postoperative surveillance. Methods: Patients with intracranial atypical meningiomas who underwent resection between 2000-2015 at a single institution were identified. Patients receiving adjuvant RT (n=51), or RT within the first year of surgery before tumor progression/recurrence (P/R), were compared to those undergoing initial surveillance (n=179). The primary endpoints were radiographic evidence of P/R and time to P/R from surgery. Results: A total of 230 patients were identified. Fifty-one (22%) patients received upfront adjuvant RT, while 179 (78%) underwent surveillance. Compared to the surveillance group, patients who received adjuvant RT had larger tumors (5.2 cm versus 4.6 cm; p=0.04), were more likely to have undergone subtotal resection (65% versus 26%; p<0.01), and more often had bone invasion (18% versus 7%; p=0.02). On multivariable analysis, receipt of adjuvant RT was associated with a lower risk of P/R compared to surveillance (HR=0.21 [95% CI 0.11-0.41]; p<0.01). Patients who initially underwent surveillance and then received salvage RT at time of P/R had a shorter median time to local progression following RT compared to patients who developed local P/R following upfront adjuvant RT (19 versus 64 months, respectively; p<0.01). Conclusion: Upfront adjuvant RT was associated with improved local control in atypical meningiomas irrespective of extent of initial resection compared to surveillance. Early adjuvant RT should be strongly considered following gross total resection of atypical meningiomas.