Adjuvant Radiotherapy For Intracranial Atypical And Malignant Meningiomas In Adult Patients

Abstract BACKGROUND Meningiomas, the most common primary brain tumor, account for more than one third of all primary CNS tumors. High-grade meningiomas, WHO grade II and III, comprise between 16%-24% of total meningiomas and are more aggressive, recur more frequently, and portend a worse prognosis than WHO grade I meningiomas. Adjuvant radiation of high-grade meningiomas, while not uncommon, remains variably described in current literature. To assess our institution’s radiation protocol, we examined our cohort of over 200 high-grade meningiomas. METHODS We queried our hospital’s EHR system for surgically resected meningiomas from January 2013 to December 2019. Of 286 results identified, 24 patients met the inclusion criteria: 1) histologically confirmed WHO grade II or III meningioma, 2) primary resection coupled with adjuvant radiation therapy, and 3) no chemotherapy. Only one WHO grade III meningioma met inclusion criteria. Patients with NF2 were excluded. Patient demographics, radiation dosage, fraction number, and dates of surgery, radiation onset, recurrence, and most recent follow-up were recorded. RESULTS Median age at surgery was 56.2 years (± 11.1, range 37.8 – 81.7), and males comprised 70.8% (n = 17) of the population. Only FSRT or IMRT were employed. The most frequent dosage was 55.8 Gy across 31 fractions with a median time to radiation of 2.7 months (± 3.0, range 1.0 – 12.6). 5 out of 24 patients experienced recurrence, which did not include the WHO III tumor. Median time to recurrence was 3.0 years (± 2.0, range .3 – 5.8). Median follow up was 3.5 years (± 2.2, range .3 – 9.3). CONCLUSIONS A fraction of our population experienced recurrence, regardless of grade II or grade III pathology. FSRT remains a safe and effective adjuvant therapy for high-grade meningioma after surgical resection. Future prospective studies comparing differing radiation modalities should be conducted.