Neoadjuvant Stereotactic Radiosurgery for Large Brain Metastases: An International, Multicenter, Single-Arm Phase II...

Area of Science:

• Neurosurgery
• Radiation Oncology
• Oncology

Background:

• Neoadjuvant stereotactic radiosurgery (SRS) may reduce risks of radiation necrosis (RN) and meningeal recurrence compared to adjuvant SRS for brain metastases (BrMets).
• A multicenter phase II trial investigated neoadjuvant SRS for large BrMets.

Purpose of the Study:

• To evaluate the safety and efficacy of single-fraction neoadjuvant SRS for large BrMets.
• To assess the primary endpoint of 1-year Grade 2+ RN rate and secondary endpoints including overall survival and intracranial progression-free survival.

Main Methods:

• 35 patients with index and nonindex BrMets were treated with single-fraction SRS targeting the index lesion, followed by resection.
• Nonindex lesions received definitive SRS.
• Primary endpoint: 1-year Grade 2+ RN rate. Secondary endpoints: overall survival, intracranial progression-free survival, local failure, leptomeningeal disease, and pachymeningeal disease.

Main Results:

• No patients developed Grade 2+ RN.
• 1-year local failure rate was 18.0%.
• 1-year rates for leptomeningeal and pachymeningeal disease were 2.9% and 3.2%, respectively. Median overall survival was 13.8 months.

Conclusions:

• Neoadjuvant SRS for BrMets resulted in no symptomatic RN and lower meningeal failure rates than historical postoperative SRS.
• High local failure rates indicate potential for dose or margin optimization in neoadjuvant SRS protocols.