Post-radiosurgical edema associated with parasagittal and parafalcine meningiomas: a multicenter study

Abstract

Stereotactic radiosurgery (SRS) offers a high degree of tumor control for benign meningiomas. However, radiosurgery can occasionally incite edema or exacerbate pre-existing peri-tumoral edema. The current study investigates the incidence, timing, and extent of edema around parasagittal or parafalcine meningiomas following SRS. A retrospective multicenter review was undertaken through participating centers in the International Gamma Knife Research Foundation (previously the North American Gamma Knife Consortium or NAGKC). All included patients had a parafalcine or parasagittal meningioma and a minimum of 6 months follow up. The median follow up was 19.6 months (6-158 months). Extent of new or worsening edema was quantitatively analyzed using volumetric analysis; edema indices were longitudinally computed following radiosurgery. Analysis was performed to identify prognostic factors for new or worsening edema. A cohort of 212 patients comprised of 51.9 % (n = 110) females, 40.1 % upfront SRS and 59.9 % underwent adjuvant SRS for post-surgical residual tumor. The median tumor volume at SRS was 5.2 ml. Venous sinus compression or invasion was demonstrated in 25 % (n = 53). The median marginal dose was 14 Gy (8-20 Gy). Tumor volume control was determined in 77.4 % (n = 164 out of 212 patients). Tumor edema progressed and then regressed in 33 % (n = 70), was stable or regressed in 52.8 % (n = 112), and progressively worsened in 5.2 % (n = 11). Tumor location, tumor volume, venous sinus invasion, margin, and maximal dose were found to be significantly related to post-SRS edema in multivariate analysis. SRS affords a high degree of tumor control for patients with parasagittal or parafalcine meningiomas. Nevertheless, SRS can lead to worsening peritumoral edema in a subset of patients such as those with larger tumors (>10 cc) and venous sinus invasion/compression. Long-term follow up is required to detect and appropriately manage post-SRS edema.

Multimodal treatment of parasagittal meningiomas: a single-center experience

“…The optimal treatment thus far has been described as a Simpson Grade I resection, although this procedure can only be successfully achieved in fewer than 25% of patients because of invasion of the superior sagittal sinus. 22,26 Even after radical resection, meningioma recurrence rates ranging from 8% to 13% have been reported. 3,13,16 In most cases, the venous sinus is only partially obstructed, thus preventing total tumor resection.…”

“…1 After several surgeries, a high percentage of patients (33%) in our series were diagnosed with atypical or malignant meningioma. 22,27 This unusually high incidence of atypical and malignant meningiomas may be explained by the tertiary care status of the Medical University Hospital Vienna. 22,27 All patients with malignant meningiomas and 2 patients with atypical meningiomas received fractionated radiation therapy of 54-60 Gy to the resection cavity after microsurgical resection and prior to the first GKRS.…”

“…22,27 This unusually high incidence of atypical and malignant meningiomas may be explained by the tertiary care status of the Medical University Hospital Vienna. 22,27 All patients with malignant meningiomas and 2 patients with atypical meningiomas received fractionated radiation therapy of 54-60 Gy to the resection cavity after microsurgical resection and prior to the first GKRS. Despite this fact, malignant meningioma recurred in a significantly shorter time after microsurgery than the WHO Grade I or Grade II tumors.…”

“…Our patient series provides long-term follow-up data after microsurgery alone, radiosurgery alone, or the two combined for parasagittal meningiomas of all WHO grades with follow-up times that are among the longest reported. 16,21,22…”

The radiosurgery fractionation quandary: single fraction or hypofractionation?

“…Tumor volume >10 cc and venous sinus invasion/ compression were factors predicting post-SRS edema. 51 Two large retrospective series on gamma knife-based SRS for cavernous sinus (n = 159) and petroclival meningiomas (n = 168) from the University of Pittsburgh Medical Center (UPMC) showed long-term local control in excess of 90% in 10 years with complication rates of 7%-8%. 52,53 The median dose used for those 2 series was 13 Gy in a single fraction.…”