Long-Term Outcomes and Symptom Response Following Hypofractionated Stereotactic Radiotherapy (hSRT) for Intracranial Meningioma.

Abstract

Various radiation dosing regimens exist due to tumor size, location, and patient preference. This study evaluated the long-term outcomes of patients with benign meningiomas treated with hSRT at our institution. This is a retrospective review of all patients diagnosed with meningioma at our institution who received hSRT (5 fractions). Clinical data, including tumor location, size, prior treatments, demographics, radiation dosimetric information, tumor response, and survival were collected. Kaplan-Meier curves were used to assess local control. Acute and late toxicities were evaluated. Patients were included for analysis if they had at least one post-treatment MRI following therapy. 108 patients with benign meningiomas treated between 2013 and 2022 were identified, with 92 included for analysis (n=16 excluded due to lack of follow-up). With median follow-up of 28 months, the 1-year, 3-year, and 5-year local control rates were 98%, 93%, and 87% respectively. Fifty-three (58%) patients had partial improvement or resolution of presenting symptoms after completing radiation treatment. When conducting a subgroup analysis excluding patients previously treated with radiation, local control improved to 99%, 97%, and 94% at 1, 3, and 5 years, respectively. Seventeen patients (18%) had G1 or G2 toxicities, with 3 of them experiencing G2 radionecrosis. Tumors were categorized by size and Chi-squared analysis showed no difference in the rate of failure (χ²=0.6, p=0.73). The SRT regimen of 25 Gy in 5 fractions effectively achieves local control and safety in benign meningiomas. These findings highlight the need for further clinical studies to better understand WHO grade 1 meningiomas.