ROCHESTER, Minn. — Mayo Clinic researchers led a multicenter study that found dividing radiation into several treatments, known as fractionated stereotactic radiosurgery, reduced the risk of cancer returning after surgery for brain metastases and was associated with improved survival compared with delivering radiation in a single treatment.

The findings are being presented today at the 2026 American Society for Radiation Oncology (ASTRO) Annual Meeting in Boston.

Brain metastases, also called metastatic brain tumors, are cancerous tumors that spread to the brain from elsewhere in the body. Radiation therapy is a standard treatment after surgery, but researchers note that about 30% to 40% of patients experience cancer recurrence at the surgical site despite treatment with single fraction radiosurgery.