Dose-effect relationship of linear accelerator based stereotactic radiotherapy for brain metastases

OBJECTIVE: The purpose of this study is to reveal the dose-effect relationship of linear accelerator (LINAC)-based stereotactic radiotherapy (SRT) in patients with brain metastases (BM). MATERIALS AND METHODS: The PubMed, Cochrane, and Web of Science databases were used to identify studies that reported local tumour control after LINAC-based SRT in patients with BMs. Studies of other approaches that could affect local tumour control, such as whole brain radiotherapy, targeted therapy, and immunotherapy, were excluded from the dose-effect relationship analysis. Data extracted included patient and treatment characteristics and tumour local control. Probit model in XLSTAT 2016 was used for regression analysis, and P < 0.05 was set as the statistically significant level. RESULTS: After literature screening, 19 eligible studies involving 1523 patients were included in the probit model regression analysis. There was no significant dose-effect relationship between nominal BED(10) and peripheral BED(10) versus 12-month local control probability. There were significant dose effect relationships between the centre BED(10) and the average BED(10) versus the 12-month local control probability, with P values of 0.015 and 0.011, respectively. According to the model, the central BED(10) and the average BED(10) corresponding to probabilities of 90% 12-month local control were 109.2 Gy(BED10) (95% confidence interval (CI): 88.7–245.9 Gy(BED10)) and 87.8 Gy(BED10) (95% CI: 74.3–161.5 Gy(BED10)), respectively. A 12-month local control rate of 86.9% (95% CI: 81.7–89.7%) and 85.5% (95% CI: 81.2–89.2%) can be expected at a centre BED(10) of 80 Gy and an average BED(10) of 60 Gy, respectively. CONCLUSION: For patients with BM treated with LINAC-based SRT, more attention should be given to the central and average doses of PTV. A clear definition of the dose prescription should be established to ensure the effectiveness and comparability of treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13014-023-02360-y.