What is your recommended follow-up schedule for a meningioma after definitive radiotherapy?

For grade 1 meningioma, I obtain annual follow up MRI for the first 5 years, and then at 18-month intervals from 5-10 years. After that I offer patients to have an MRI every other year and some of them will do it.

My personal approach varies from this recommendation only modestly. For patients with a newly diagnosed WHO grade I meningioma I order follow-up MRIs in a fashion very similar to this but do not stop at 10 years. There are only a few studies with follow-up for a sizeable cohort beyond a decade, but ...