Introduction: Parasagittal meningiomas are challenging due to their proximity to the superior sagittal sinus and draining veins, often limiting gross total resection. Limited data exist on the efficacy of Gamma Knife Radiosurgery (GKSRS) in this progression-prone region. We evaluated the effectiveness of GKSRS in achieving tumor control.
Methods: A retrospective analysis was conducted at a single academic institution from 2015 to 2023, analyzing predictors of progression via univariable and multivariable Cox regression analyses.
Results: Thirty patients were included; 86.7 % underwent resection prior to GKSRS. At presentation, 47 % had primary and 53 % had recurrent tumors. Median tumor volume was 2.0 cm³ and diameter was 1.7 cm. Median follow-up was 33 months; mortality was 16.7 %. 80 % received single-fraction GKSRS; 20 % received five fractions. Median dose was 1500 cGy. At last follow-up, 80 % had local tumor control. One patient had pre-treatment edema; none developed post-treatment edema. Median progression-free survival (PFS) was 70.6 months. WHO grade I tumors had longer PFS than grade II/III (78.5 vs. 32.4 months, p = 0.011). Older age predicted progression on univariable (HR: 1.2, p = 0.028) and multivariable analysis (HR: 1.2, p = 0.036). Tumor volume, dose, extent of resection, and recurrence status were not significant predictors.
Conclusion: Our study provides evidence suggesting that GKSRS may be a safe and potentially effective treatment for select parasagittal meningiomas. The slightly lower control rate compared with other sites likely reflects the higher prevalence of WHO grade II tumors in this region. A nuanced interpretation of our findings, along with further multi-institutional validation, is necessary.
Keywords: Fractionation; Gamma knife stereotactic radiosurgery (GKSRS); Parasagittal meningioma; Radiosurgical outcomes; Tumor control.
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