Fractionated SRS Beats Single-Dose Radiation After Brain Tumor Surgery
A phase III trial shows fractionated radiosurgery sharply improves local control and survival after surgical removal of large brain metastases.
Summary
A randomized phase III trial found that delivering stereotactic radiosurgery (SRS) in three to five sessions after surgical removal of large brain metastases significantly outperforms single-dose SRS. One-year local control improved from 81% to 87%, overall survival jumped from 20.2 to 28.6 months, and fewer patients needed salvage whole-brain radiation — all with no added toxicity. Conducted through the Alliance Clinical Network, the A071801 trial enrolled patients with up to four brain metastases, including at least one resected lesion 2 cm or larger. Experts at the ASTRO annual meeting called fractionated SRS the new standard of care for postoperative radiotherapy after resection of larger brain metastases, upgrading the evidence base from retrospective data to a randomized controlled trial.
Detailed Summary
Brain metastases — tumors that have spread from other parts of the body to the brain — are a leading cause of cancer-related death and disability. After surgical removal, radiation to the surgical bed is standard practice to reduce the risk of local recurrence. Until now, a single high-dose fraction of stereotactic radiosurgery (SRS) was considered the standard, but recurrence rates remained troublingly high, especially for larger lesions.
The Alliance A071801 randomized phase III trial directly compared single-fraction SRS with fractionated SRS (27 Gy delivered in three fractions) in patients with up to four brain metastases, including at least one resected lesion measuring 2 cm or more. Results presented at the ASTRO 2026 annual meeting in Boston showed one-year surgical-bed control improved from 81% with single-fraction SRS to 87% with fractionated SRS — a meaningful gain in a population where recurrence has historically been difficult to prevent.
Beyond local control, fractionated SRS delivered important secondary benefits. Overall survival improved substantially, from 20.2 months to 28.6 months, and fewer patients in the fractionated group required salvage whole-brain radiation therapy, which carries significant cognitive side effects. Critically, these gains came with no increase in treatment-related toxicity, addressing a key concern about delivering multiple radiation sessions to a sensitive area.
Clinical experts at ASTRO declared fractionated SRS the new postoperative standard of care when external beam radiotherapy is chosen after upfront brain metastasis resection. This upgrades the evidence from retrospective series to the gold standard of a randomized controlled trial, a significant shift for oncology practice.
Caveats remain. The overall survival improvement is a secondary endpoint and its mechanisms need further study. The trial focused on larger metastases, so results may not extend to smaller lesions. Longer follow-up data will help clarify durability of benefit and late toxicity profiles.
Key Findings
- Fractionated SRS improved one-year surgical-bed local control from 81% to 87% versus single-fraction SRS.
- Overall survival improved by over 8 months (20.2 to 28.6 months) with fractionated SRS.
- Fewer patients required salvage whole-brain radiation therapy in the fractionated SRS group.
- No increase in toxicity was observed with fractionated versus single-fraction SRS.
- Phase III randomized data now support fractionated SRS as the new postoperative standard of care for larger brain metastases.
Methodology
This is a meeting coverage news report summarizing results from the Alliance A071801 randomized phase III trial presented at the ASTRO 2026 annual meeting. The evidence basis is a multicenter randomized controlled trial, the highest tier of clinical evidence. Full peer-reviewed publication has not yet been cited, so primary data should be verified upon journal release.
Study Limitations
Full peer-reviewed publication of the A071801 trial has not been referenced; findings are based on meeting presentation coverage and should be confirmed upon journal publication. The overall survival improvement is a secondary endpoint and requires further mechanistic and confirmatory analysis. Results may not generalize to patients with smaller brain metastases or those not undergoing upfront surgical resection.
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