BOSTON — The Alliance A071801 multicenter randomized phase III trial compared fractionated stereotactic radiosurgery to single-fraction stereotactic radiosurgery for patients with resected brain metastases. The trial findings were presented at the 2026 American Society for Radiation Oncology Annual Meeting in Boston.

The study enrolled 242 patients with one to four brain metastases, including at least one metastasis larger than 2 centimeters that had been surgically removed. Patients were randomly assigned between 2019 and 2022 to receive either single-fraction stereotactic radiosurgery or fractionated stereotactic radiosurgery delivered in three or five sessions.

Median overall survival was 29 months for patients who received fractionated stereotactic radiosurgery, compared with 20 months for patients who received single-fraction treatment. Fractionated treatment was associated with a 31% lower risk of death compared to single-fraction treatment.

One year after treatment, 87% of patients who received fractionated stereotactic radiosurgery had no recurrence at the surgical site, compared with 81% of patients who received single-fraction treatment. Researchers found no difference in side effects or complications between the fractionated and single-fraction treatment groups. Paul D. Brown, a radiation oncologist, said the treatment controls disease and is associated with improved survival.

Ayal A. Aizer, a radiation oncologist, said the evidence base has shifted, moving fractionated radiosurgery from a reasonable practice supported by retrospective data to one backed by a randomized phase III trial.

Rupesh Kotecha, a radiation oncologist, summarized the clinical implication of the data, stating that if postoperative external beam radiotherapy is chosen after upfront resection, then postoperative fractionated radiosurgery is the new standard of care. He added that for patients with larger brain metastases, three to five sessions should now be considered a standard postoperative treatment.

Why It Matters

An estimated 200,000 people develop brain metastases each year in the United States. The Alliance A071801 trial was part of a broader effort by the Alliance for Clinical Trials in Oncology to evaluate postoperative radiation strategies for brain metastases, building on earlier phase II trials such as A071301.

The Alliance A071801 trial was registered under clinical trial identifier NCT04114981 on ClinicalTrials.gov, detailing its protocol and objectives. The trial was funded by the National Cancer Institute under grants U10CA180821 and U10CA180882.

What's New

A study titled "Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis" was published in 2026 in International Journal of Radiation Oncology*Biology*Physics. Research titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis was published in 2026 in International Journal of Radiation Oncology*Biology*Physics.

Chad Rusthoven, a radiation oncologist, said the findings suggest that patients can now have a more individualized discussion about whether focused radiosurgery or whole brain treatment is right for them.

How Sources Differ

Regarding fraction stereotactic radiosurgery, International Journal of Radiation Oncology*Biology*Physics published a study titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis in 2026 in International Journal of Radiation Oncology*B. The Alliance for Clinical Trials in Oncology A071801 trial protocol stated that the Alliance A071801 multicenter randomized phase III trial compared fractionated stereotactic radiosurgery to single-fraction stereotactic radiosurgery for patients with resected brain metastases.

Regarding stereotactic radiosurgery, International Journal of Radiation Oncology*Biology*Physics published a study titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis in 2026 in International Journal of Radiation Oncology*B. The Alliance for Clinical Trials in Oncology A071801 trial results showed that one year after treatment, 87% of patients who received fractionated stereotactic radiosurgery had no recurrence at the surgical site, compared with 81% of patients who received single-fraction treatment.

Regarding fraction stereotactic radiosurgery, International Journal of Radiation Oncology*Biology*Physics published a study titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis in 2026 in International Journal of Radiation Oncology*B. The Alliance for Clinical Trials in Oncology A071801 trial protocol noted that patients were randomly assigned between 2019 and 2022 to receive either single-fraction stereotactic radiosurgery or fractionated stereotactic radiosurgery delivered in three or five sessions.

Regarding stereotactic radiosurgery, International Journal of Radiation Oncology*Biology*Physics published a study titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis in 2026 in International Journal of Radiation Oncology*B. The Alliance for Clinical Trials in Oncology A071801 trial results indicated that median overall survival was 29 months for patients who received fractionated stereotactic radiosurgery, compared with 20 months for patients who received single-fraction treatment.

Regarding fraction stereotactic radiosurgery, International Journal of Radiation Oncology*Biology*Physics published research titled Alliance A071801 Phase III Trial Postoperative Single Fraction Stereotactic Radiosurgery (SRS) vs. Fractionated SRS (fSRS) for Resected Brain Metastasis in 2026 in International Journal of Radiation Oncology*.