Primary or Salvage Stereotactic Radiosurgery for Meningiomas Invading the Superior Sagittal Sinus.

Background and objectives: Meningiomas invading the superior sagittal sinus (SSS) present significant challenges for surgical management. Stereotactic radiosurgery (SRS) is increasingly used as a primary or salvage management in these difficult cases. The aims of this study were to evaluate the rate of long-term tumor control and the long-term neurological outcomes.

Methods: The authors retrospectively reviewed outcomes in 248 patients (152 females, 67.3%; median age, 61 years) with SSS invasive meningiomas who underwent primary or salvage SRS during a 22-year interval. The clinical presentation, radiographic characteristics, and neurological function of each patient were recorded. A total of 140 patients underwent resection before SRS for their SSS meningiomas. Overall, 56% of the patient had tumors involve the posterior one-third of the SSS; 51.6% of patients presented with peritumoral edema before SRS.

Results: The 1-, 2-, 5-, and 10-year local tumor control (LTC) rates were 97.7%, 94.1%, 85.7%, and 78.3%, respectively. Upfront SRS for SSS-invading meningiomas provided LTC comparable with that observed with salvage SRS for histologically confirmed WHO Grade I meningiomas (hazard ratio 0.86, CI 95% 0.33-2.24, P = .76). Tumor volumes <5.2 cc predicted better LTC (hazard ratio 5.1, CI 95% 1.9-19.3, P = .03). The median overall survival after SRS was 14.6 years. Ten patients (4%) died related to documented local intracranial tumor progression. A total of 12 patients (4.8%) developed symptomatic adverse radiation effects at median duration post-SRS of 14 months (range 2-182 months). Motor function improved in 20% patients who presented with motor weakness, after SRS.

Conclusion: SRS is safe and effective in managing small to medium sized SSS invading meningiomas, especially when the tumors involve the posterior one-third of the SSS. For larger SSS meningioma with symptomatic mass effect, adjuvant SRS for residual or recurrent tumors provides long-term tumor control.