Preliminary Results of Two-Stage Radiosurgery for Brain Metastases

Purpose of the study. To perform a preliminary assessment of local control after two-stage staged radiosurgery in patients with metastatic brain lesions. Patients and methods. For staged radiosurgery, large lesions measuring ≥ 3 cm in the largest dimension were selected. The regimen consisted of delivering 12 Gy in a single fraction at the first stage and 14 Gy in a single fraction at the second stage, with a 14‑day interval between the stages. If additional smaller lesions were present, they were irradiated simultaneously using the standard SRS technique in a single fraction with a dose per fraction (DPF) of 18–24 Gy. The prospective analysis included 32 patients of both sexes aged 34 to 76 years (mean age 57 ± 3.3 years) with brain metastatic lesions ≥ 3 cm in the largest dimension, or located in close proximity to critical brain structures, who underwent a two-stage course of staged radiosurgery at the National Medical Research Centre for Oncology. Results. The evaluation of target lesion volumes was based on brain MRI performed before treatment, prior to the second stage, and one month after completion of treatment. At the one-month follow-up after the treatment course, local control was achieved in the vast majority of clinical cases. Sixteen lesions demonstrated a volume reduction of more than 70 % from baseline, eleven showed a reduction of more than 50 %, eight lesions exhibited a decrease of less than 50 %, and one lesion demonstrated a negative response. Conclusion. Two-stage staged radiosurgery for brain metastases demonstrated satisfactory local control in patients with various primary tumor sites. The positive dynamics observed at this stage suggest the potential for favorable long-term outcomes.