2025 Proffered Presentations
S251: EVALUATING ADJUVANT RADIATION THERAPY FOR GRADE 2 MENINGIOMA: A MULTI-INSTITUTIONAL ANALYSIS
Saksham Gupta; Harshit Arora; Velina Chavarro; Noah Nawabi; Rahya Karanth; Samantha Sadler; Lila Medeiros; Neel Mehta; Rohan Jha; Marcelle Altshuler; Joshua Bernstock; Timothy Smith; Timothy Smith; Omar Arnaout; Brigham and Women's Hospital
Background and Objective: Grade 2 meningiomas are associated with variable rates of local recurrence. The role of adjuvant radiation therapy to reduce the risk of local progression is debated.
Methods: This was a multi-institutional retrospective cohort study including all adult patients with new diagnosed and previously untreated grade 2 meningioma treated at Mass General Brigham hospitals from 2006-2020. Cox proportional-hazards modeling was used to analyze the impact of adjuvant RT on progression-free survival (PFS).
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Results: A total of 429 patients with grade 2 meningioma were included (median age 59.7 years, 61.5% female). Gross total resection (GTR) was achieved in 298 cases (69.5%). Among 284 cases with quantified Ki67 proliferation indices (PIs), the median PI was 10.0% (IQR 6.7-15%). In total, 18.8% cases had adjuvant RT after GTR and 48.9% of cases had adjuvant RT after STR.
The median follow-up was 5.2 years. Adjuvant RT was not associated with PFS after GTR (hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.48-1.52), but was associated with improved PFS after STR (HR 0.54; 95% CI 0.31-0.94).
These findings remained consistent after adjusting for age, sex, location, and size. Adjuvant RT was associated with improved PFS for cases with Ki67 index equal to or over 10% (HR 1.89; 95% CI 1.05-3.60; p=0.034) but not below 10% (HR 0.94; 95% 0.47-1.67; p=0.93). There were 74 patients (23.9%) who were offered adjuvant RT but did not receive it, and there was no difference in PFS between patients who were offered adjuvant RT and either did or did not receive it (p=0.63).
Cases with GTR were determined by operative reports to have Simpson 1 (n=229, 76.8%), Simpson 2 (n=56, 18.8%), or Simpson 3 (n=13, 4.4%) extent of resection. Cases with Simpson 1, 2, and 3 grade resections received adjuvant RT in 18.3%, 16.1%, and 41.7% of cases, respectively (Figure 3). The relationship between adjuvant RT and improved PFS trended towards a stronger association after Simpson Grade 3 resection after multivariate adjustment for age, sex, and size, but this was not statistically significant
Conclusion: Adjuvant RT for grade 2 meningioma reduces tumor progression after STR, but not GTR in this cohort. These findings contribute to the ongoing debate regarding the role of adjuvant RT, suggesting a tailored approach to optimize outcomes.