How do you approach treatment of an optic nerve sheath meningioma?

I typically do 50.4 in 28 fractions with a stereotactic technique. We use both co-planar and non-coplanar arcs. I keep the optics point max to 54 Gy.

Several single institution series including: MacLean et al. IJROBP 2013, Bloch et al. (UCSF) JCNeuroSci 2012, Ratnayake et al. (Australia) JCNeuroSci ...

We have been treating optic nerve sheet meningiomas (ONSM) at Jefferson for over two decades with SRT technique, delivering a dose of 5400 cGy in 180 cGy daily fractions, unless the tumor has a significant posterior extension toward the anterior clinoid/chiasm, in which case a lower dose of 5040-522...

50.4 at 1.8 Gy per fraction with protons.

No biopsy. I keep the dose to 5040/180 cGy due to already compromised ON. No hot spots over optics. Guy on treatment now already getting vision back.