Introduction: Atypical meningiomas (WHO Grade II) are associated with high recurrence rate despite surgical resection. The optimal management of these tumors has not been well delineated. This study aims to evaluate the role of stereotactic radiosurgery (SRS) in controlling progression of these lesions.
Methods: 59 patients were treated, either immediately after surgery (N = 26) or at the time of radiographic progression or treatment failure (N = 33). 38 patients had not received any prior radiation. Cyberknife SRS was delivered with a median marginal dose of 22 Gy (range, 15 - 35) in 1 to 5 fractions (median, 1), targeting a median tumor volume of 3.95 cm3 (range, 0.3 - 26).
Results: With a median follow-up of 30 months (range, 3 - 80), the 12-, 24-, and 36-month control rates were 90%, 87%, and 72%, respectively. There were 3 cases of radiation toxicity, one of radiation necrosis on imaging that was clinically asymptomatic, and two with neurologic sequela stemming from radiation induced edema (obstructive hydrocephalus and seizure, respectively) that both self-resolved. Of the 38 radiation-naïve patients, there were 12-, 24- and 36-month control rates of 97%, 97%, and 78%, respectively.
Conclusions: Stereotactic radiosurgery is a safe and effective treatment modality for local control of delayed progression following surgical resection of atypical meningiomas.
Patient Care: We present a study detailing the efficacy of stereotactic radiosurgery for treatment and control of atypical meningiomas after initial surgical resection. Stereotactic radiosurgery is a valuable treatment modality for local control and to prolong progression free survival in patients with atypical meningiomas.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Describe the significance and treatment of atypical meningiomas
2) Describe the stereotactic radiosurgery (SRS) strategy for targeting atypical meningiomas
3) Understand the evidence behind SRS treatment of atypical meningiomas for optimal tumor control and progression free survival