Linear-accelerator-based hypofractionated radiotherapy for large brain metastases in Korea: a retrospective cohort study

초록

Purpose: The use of hypofractionated stereotactic radiotherapy (HFSRT) for large brain metastases has been steadily increasing. This study aimed to evaluate the efficacy and safety of linear accelerator-based HFSRT as a primary treatment option for large brain metastases without prior surgical resection. Methods: Between December 2013 and April 2022, 17 patients with brain metastases larger than 10 cm3 underwent HFSRT. Local control was assessed on a per-lesion basis. HFSRT was delivered using linear accelerator equipment (Novalis Tx; Varian Medical Systems). Results: Fourteen patients (82.4%) received 3 treatment fractions, while 2 patients received 2 and 5 fractions, respectively. Radiation-induced acute toxicity was reported in one case within the 3-fraction group, presenting with headache and vomiting. For multiple lesions, the median time to local failure was 0.2 months, compared with 2.8 months for single lesions (P= 0.011). The 1-year local control rate was 68.2%. The 1-year overall survival (OS) rate was 29.4%, and the 2-year OS rate was 11.8% for the total cohort. Conclusion: Linear accelerator-based HFSRT is both effective and safe for the treatment of large brain metastases and may be considered a primary treatment approach. In this study, the 1-year local control rate and 1-year survival rate were 68.2% and 29.4%, respectively. To reduce the risk of posttreatment swelling, the total dose should not exceed a biologically effective dose of 64.65 Gy, and delivery in 3 fractions appears safe with respect to radiation toxicity.

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