Khaboushan et al. [2] provide a very interesting systemic review & meta-analysis of SRS for intraventricular meningiomas. The rarity of the disease and literature of this subject is makes this contribution especially pertinent. The safety efficacy of radiosurgery in general is very well established in the literature specially for skull base (eg cavernous sinus, petro-clival region) [4]. In meningiomas WHO I SRS is reaching a long term efficacy demonstrated to be equivalent to a radical resection which is rarely affordable in skull base lesions [3].

In spite of the similarity of the gross histology meningiomas depending on their location can have very different rate of toxicity after radiosurgery and are demonstrated now to carry significantly different biological markers [5]. Symptomatic side effects of SRS in skull base meningiomas related to edematous reaction are very rare in skull base meningiomas but are occurring from time to time in midline meningiomas [1], but what about intraventricular ones?

Jason Sheehan is supervising here a new and very rigorous and interesting analyse of the literature and, in spite of the limitations clearly exposed by the authors, is providing a good evidence of the safety of SRS in this very specific form of meningiomas. With 11% of the patients presenting with symptomatic edema requiring proactive management the rate of toxicity is very reasonable but much higher than what is observed in skull base ones. In terms of tumor control a 2 years PFS of 95% is nice but in meningioma a 2 years follow up is clearly not sufficient to evaluate SRS long term efficacy.