Fractionated radiation improves survival for brain metastasis patients

Findings from the phase 3 Alliance A071801 trial, presented at the 2026 American Society for Radiation Oncology (ASTRO) Annual Meeting, indicate that fractionated stereotactic radiosurgery (SRS) is more effective than single-fraction SRS for patients following brain metastasis resection.

The study, which involved 242 patients with one to four brain metastases, showed that at one year, surgical bed control was 87% for those receiving fractionated SRS compared to 81% for those receiving single-fraction SRS. Additionally, median overall survival was significantly higher for the fractionated group at 29 months, compared to 20 months for the single-fraction group.

Researchers note that dividing radiation into multiple treatments allows for a higher total dose while giving healthy brain tissue time to recover. This approach helps address the challenge of eliminating microscopic cancer cells without causing significant necrosis in large resection cavities. While fractionation is expected to become the standard of care for typical patients, experts suggest single-fraction SRS may still be a reasonable option for patients with smaller lesions or those with a guarded prognosis who prefer a single treatment session.