Mitotic count and Ki-67 index were independently associated with early and long-term PFS, whereas male sex, older age, and subtotal resection predicted tumor-related mortality.<h4>Conclusions</h4>Early RT provides a durable and clinically meaningful PFS benefit over late RT in WHO grade 2 meningiomas, including after GTR, without conferring an OS advantage. Here, MKI67 is linked to meningioma.