title: Proton therapy for atypical meningiomas.
abstract: We report clinical outcomes of proton therapy in patients with World Health Organization grade 2 (atypical) meningiomas. Between 2005 and 2013, 22 patients with atypical meningiomas were treated to a median dose of 63 Gy (RBE) using proton therapy, as an adjuvant therapy after surgery (n = 12) or for recurrence or progression of residual tumor (n = 10). Six patients had presumed radiation-induced meningiomas, but none had received prior radiotherapy for their meningioma. The median follow-up time after radiation was 39 months (range 7-104) and all patients remain alive at last follow-up. The 5-year estimate of local control was 71.1% (95% CI 49.3-92.9%). The 5-year estimate of local control was 87.5% following a radiation dose >60 Gy (RBE), compared to 50.0% for ≤ 60 Gy (RBE) (p = 0.038). The 5-year estimate of neuraxis dissemination was 5% (95% CI 0-14.6%) and 6.2% (95% CI 0-18.2%) for metastases outside of the central nervous system. Radiation necrosis was observed in one patient with a history of prior cranial irradiation. Fractionated proton therapy was associated with favorable tumor control rates for grade 2 meningiomas. Prospective studies are needed to define the optimal radiation dose for high-grade meningiomas.
authors: Department of Radiation Oncology, Indiana University School of Medicine, 535 Barnhill Dr RT041, Indianapolis, IN, 46202, USA, markmcdonaldmd@gmail.com.
authors: Mark W
authors: MW
authors: McDonald
authors: David A
authors: DA
authors: Plankenhorn
authors: Kevin P
authors: KP
authors: McMullen
authors: Mark A
authors: MA
authors: Henderson
authors: Edward J
authors: EJ
authors: Dropcho
authors: Mitesh V
authors: MV
authors: Shah
authors: Aaron A
authors: AA
authors: Cohen-Gadol
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008579:Meningioma / Q000473:pathology / Q000532:radiotherapy*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy*; D009367:Neoplasm Staging; D011379:Prognosis; D061766:Proton Therapy; D012189:Retrospective Studies; D016879:Salvage Therapy; D015996:Survival Rate; D055815:Young Adult