This study is for adults with a specific type of brain tumor called Grade II Meningioma. After surgery to remove the tumor, patients will either be watched carefully (observation) or receive radiation therapy. Radiation therapy uses powerful x-rays to kill any leftover cancer cells. The study will help understand if adding radiation after surgery helps more than just watching.

Key Points:

• The study compares observation to radiation therapy over 6.5-7 weeks.
• Participants will have follow-up visits for up to 10 years.
• There are specific eligibility criteria, like age (18+), and certain health conditions that might exclude participation.

Participants will have regular MRI scans (an imaging test) and blood samples taken. They must be able to undergo these tests, even if they need sedation for MRI. Women of childbearing age need a negative pregnancy test and must agree to use contraception if they receive radiation. This study helps decide the best treatment option after surgery and could lead to better care for future patients with this type of tumor.