title: Post-Treatment Edema after Meningioma Radiosurgery is a Predictable Complication.
abstract: Symptomatic post-treatment edema (PTE) causing seizures, focal deficits, and intracranial hypertension is a rather common complication of meningioma radiosurgery. Factors associated to the occurrence of PTE still needs to be clarified. We retrospectively analyzed our patients' data to identify factors associated with the development of symptomatic PTE. Supposed risk factors were systematically analyzed. Between July 2007 and March 2014, 245 meningiomas in 229 patients were treated by a single fraction or multisession radiosurgery (2-5 fractions) or hypofractionated stereotactic radiotherapy (6-15 fractions) using the CyberKnife system (Accuray Inc., Sunnyvale, CA) at the University Hospital of Messina, Italy. Local tumor control was achieved in 200 of 212 patients with World Health Organization (WHO) Grade I meningiomas (94%) at a mean follow-up of 62 months. Symptomatic PTE on MRI was diagnosed in 19 patients (8.3%) causing seizure (n=17, 89%), aggravating headache (n=12, 63%), or focal deficits (n=13, 68%). Four variables were found to be associated with the likelihood of edema development, including tumor volume > 4.5 mL, non-basal tumor location, tight brain/tumor interface, and atypical histology. Nonetheless, when multivariate logistic regression analysis was performed, only tumor volume and brain-tumor interface turned out to be independent predictors of PTE development. Our results suggest that the factor associated with the risk of developing PTE is associated to characteristics of meningioma rather than to the treatment modality used. Accordingly, an appropriate patient selection is the way to achieve safe treatment and long-term disease control.
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Conti
authors.affiliation: Radiation Oncology, University of Messina.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pontoriero
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Francesca
authors.initials: F
authors.lastname: Siddi
authors.affiliation: Radiation Oncology, University of Messina.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iatì
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cardali
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Filippo F
authors.initials: FF
authors.lastname: Angileri
authors.affiliation: Neuroradiology, University of Messina.
authors.forename: Francesca
authors.initials: F
authors.lastname: Granata
authors.affiliation: Radiation Oncology, University of Messina.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pergolizzi
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Antonino
authors.initials: A
authors.lastname: Germanò
authors.affiliation: Department of Neurological Surgery, University of Messina.
authors.forename: Francesco
authors.initials: F
authors.lastname: Tomasello
keywords: brain edema; brain tumor interface; cyberknife; meningioma; stereotactic radiosurgery; vascular-endothelial growth factor