Prospective registry study of single-isocenter dynamic conformal Arc SRS for multiple brain metastases

Brain metastases occur in 20-30% of patients with malignant tumors. While stereotactic radiosurgery (SRS) offers an effective treatment option for limited brain metastases, managing symptomatic patients with multiple metastases remains challenging due to prolonged treatment times and potential neurological complications. The dynamic conformal arc (DCA) SRS technique using a single-isocenter multi-target (DCA-SIMT) approach facilitates efficient treatment of numerous lesions. This study evaluates survival outcomes and symptom control in patients treated with DCA-SIMT SRS for multiple brain metastases. A registry based analysis was conducted on 123 patients with 560 metastatic CNS lesions treated with DCA-SIMT SRS at the Franciszek Lukaszczyk Oncology Center, Poland, between August 2018 and September 2020. The median survival time was 7.17 months. Patients were assessed for survival, local control, and treatment-related symptoms. Statistical analyses included Cox regression and Kaplan-Meier survival analysis. The 6-month and 12-month survival rates were 57% and 29%, respectively. Local control was achieved in 93% of lesions. The total planning target volume (PTV) was a significant prognostic factor (p = 0.008), with an increase in PTV associated with decreased survival. Patients with PTV ≤ 10 cm³ had significantly longer survival (p = 0.007). Histopathological subtype also influenced outcomes, with sqamous non-small cell lung cancer associated with poorer survival (p = 0.003). Neurological symptoms stabilized or improved in 61% of patients post-treatment, despite a median global V12 of 11.6 cm³, which was not associated with increased toxicity. DCA-SIMT SRS is a viable option for symptomatic patients with multiple brain metastases, offering rapid, precise treatment with significant clinical benefits.