Fractionated stereotactic radiotherapy as a primary or salvage treatment for large brainstem metastasis.

Abstract

This study aimed to determine the efficacy and safety of robotic-based fractionated stereotactic radiotherapy (FSRT) in the treatment of large brainstem metastases (BSMs). Ten BSM were treated in ten patients with FSRT between January 2012 and December 2018. The median age was 61 years (range, 53-74 years) with a median Karnofsky Performance Score of 80 (range, 70-90). Four patients (40%) had received whole-brain radiotherapy prior to FSRT. The median tumor volume was 4.2 cm3 (range, 1.35-8.18 cm3) with a median prescription dose of 24 Gy (range, 16-24 Gy) delivered in 3-5 fractions (median three fractions) to the 56%-83% isodose line (median 70.5%). 1Median follow-up for the entire cohort was 14.1 months (range, 4.6-19.3 months). Five local recurrences were documented. Local control (LC) rate at 6 and 12 months was 90% and 64.2%, respectively. The median tumor volume of patients developing local recurrence was 5.42 cm3. Three patients experienced intracranial out-of-field failure for a 12-month intracranial control rate of 78.7%. Median overall survival and time to extracranial progression were 14.7 and 16.8 months, respectively. Toxicity was low with only one patient developing a new hemiparesis. Robotic-based FSRT for BSM appears to be safe with favorable LC and low toxicity even for large tumors.