Presenter(s)
J. Natarajan1, M. Campbell2, Y. Abumohsen3, H. Bhatt4, E. S. Hollis1, Y. Rauf5, M. Ewend6, D. Higgins7, C. David8, E. M. Steele9, and C. Shen9; 1University of North Carolina Hospitals, Chapel Hill, NC, 2North Carolina School of Science and Mathematics, Durham, NC, 3UNC Chapel Hill School of Medicine, Chapel Hill, NC, United States, 4UNC Chapel Hill, Chapel Hill, NC, 5Department of Neuro Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 6UNC School of Medicine, Chapel Hill, NC, 7University of North Carolina, Chapel Hill, NC, 8Department of Neurosurgery, UNC at Chapel Hill School of Medicine, Chapel Hill, NC, 9Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC
Purpose/Objective(s):
Surgical resection is the primary treatment for WHO grade 2 meningiomas, with postoperative radiotherapy (PORT) routinely recommended after subtotal resection (STR). The benefit of PORT after gross total resection (GTR) is under investigation (e.g., NRG-BN003). We aimed to characterize utilization of PORT for grade 2 meningiomas and identify patient subgroups most likely to benefit from early PORT.Materials/Methods:
We retrospectively reviewed 41 patients who underwent resection for WHO grade 2 meningioma from 2016–2025 at a single academic institution. Data collected included patient and tumor characteristics, extent of resection, timing and rationale for RT, recurrence patterns, and survival outcomes. Resection was categorized as biopsy/STR, GTR without dural resection or with radiographic residual disease (GTR2), and GTR with dural resection and no radiographic residual (GTR1). Immediate PORT was defined as RT within 6 months of surgery. Progression-free survival (PFS) and overall survival (OS) were assessed with Kaplan-Meier analysis and log-rank tests, and associations with recurrence were analyzed using Chi-square analysis.Results:
The cohort included 26 women (63%) and 15 men (37%) with a median age of 59. Median tumor size was 4.6 cm (range 1.5-7.6 cm). Resection extent was biopsy/STR (39%), GTR2 (22%), and GTR1 (39%). Immediate PORT was given after biopsy/STR, GTR2, and GTR1 in 69%, 67%, and 31% of cases, respectively. Median RT dose was 54 Gy. In GTR1/GTR2 patients, PORT was recommended primarily for concern for residual disease (64%), patient preference (27%), or aggressive subtype (9); PORT was omitted due to patient preference (50%), negative DOTATATE PET (14%), postoperative complications (14%), or other reasons (21%). Among patients not receiving immediate PORT, 63% ultimately underwent RT at a median of 22.9 months (range 10.2-98.0 months) from initial surgery. Five-year OS for the cohort was 80%, and median PFS was 21.4 months (95% CI 7.3-35.5 months). PFS did not differ by age, sex, tumor size, mitotic index, extent of resection, or receipt of immediate PORT overall. However, among patients whose tumors had =5 mitoses/high power field (HPF), immediate PORT significantly improved PFS (38.3 vs 11.7 months, p<0.05). For patients with less than GTR1 resection, immediate PORT showed a trend toward improved PFS (27.4 vs 13.7 months, p=0.055), significantly better OS (p<0.02), and fewer recurrences (p<0.02). No benefit was seen for patients with GTR1 resection.Conclusion:
Immediate PORT was associated with superior outcomes for patients with mitotically active tumors and for those without complete (GTR1) resection. While we await results from prospective trials, these findings support withholding PORT after GTR1 resection while suggesting clear utility for patients with higher-risk histology or less complete resections.