A phase II clinical trial of frameless fractionated stereotactic radiotherapy for brain metastases.

Stereotactic radiotherapy (SRT) yields high rates of local control for brain metastases, but rural/suburban patients face geographic and socioeconomic barriers to access SRT. We conducted a Phase 2 clinical trial of frameless fractionated stereotactic radiotherapy (FFSRT) for brain metastases in an integrated academic satellite network for patients ≥18-years-old with 1-4 brain metastases. Dose was based on gross tumor volume (GTV) size: < 3.0 cm, 27 Gy in 3 fractions, and 3.0-3.9 cm, 30 Gy in 5 fractions. Median follow-up was 10 months for 73 evaluable patients with median age of 68 years. Median intracranial progression free survival (PFS) was 7.1 months (95% confidence interval (CI): 5.3-not reached (NR)), median survival 7.2 months (95% CI: 5.4-NR), and there were no severe adverse events. Outcomes of this trial compare favorably with contemporary trials and this treatment strategy provides opportunities to expand SRT access to underserved populations.