Department of Human Oncology, University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI, 53792, USA.
J Neurooncol. 2019 Nov;145(2):385-390. doi: 10.1007/s11060-019-03308-7. Epub 2019 Oct 12.
The aim of this study was to determine whether a higher biological effective dose (BED) would result in improved local control in patients treated with fractionated stereotactic radiotherapy (FSRT) for their resected brain metastases.
Patients with newly diagnosed brain metastases without previous brain radiotherapy were retrospectively reviewed. Patients underwent surgical resection of at least one brain metastasis and were treated with adjuvant FSRT, delivering 25-36 Gy in 5-6 fractions. Outcomes were computed using Kaplan-Meier survival analysis and univariate analysis.
Fifty-four patients with 63 post-operative cavities were included. Median follow-up was 16 months (3-60). Median metastasis size at diagnosis was 2.9 cm (0.6-8.1) and median planning target volume was 19.7 cm (6.3-68.1). Two-year local control (LC) was 83%. When stratified by dose, 2 years LC rate was 95.1% in those treated with 30-36 Gy in 5-6 fractions (BED of 48-57.6 Gy) versus 59.1% lesions treated with 25 Gy in 5 fractions (BED of 37.5 Gy) (p < 0.001). LC was not associated with resection cavity size. One year overall survival was 68.7%, and was independent of BED. Symptomatic radiation necrosis occurred in 7.9% of patients and was not associated with dose.
In the post-operative setting, high-dose FSRT (BED > 37.5 Gy) were associated with a significantly higher rate of LC compared to lower BED regimens. Overall, 25 Gy in 5 fractions is not an adequate dose to control microscopic disease. If selecting a 5-fraction regimen, 30 Gy in five fractions appears to provide excellent tumor bed control.
本研究旨在确定接受分割立体定向放疗（FSRT）治疗的切除脑转移瘤患者中，较高的生物有效剂量（BED）是否会提高局部控制率。
回顾性分析了新诊断的无既往脑放疗脑转移患者。患者行至少 1 个脑转移瘤切除术，术后行辅助 FSRT，5-6 次分割，每次 25-36Gy。采用 Kaplan-Meier 生存分析和单因素分析计算结局。
54 例患者共 63 个术后瘤腔纳入研究。中位随访时间为 16 个月（3-60）。诊断时转移灶大小中位数为 2.9cm（0.6-8.1），计划靶区体积中位数为 19.7cm（6.3-68.1）。2 年局部控制率（LC）为 83%。按剂量分层，接受 30-36Gy 5-6 次分割（BED 48-57.6Gy）治疗的患者 2 年 LC 率为 95.1%，而接受 25Gy 5 次分割（BED 37.5Gy）治疗的患者 2 年 LC 率为 59.1%（p<0.001）。LC 与瘤腔大小无关。1 年总生存率为 68.7%，与 BED 无关。有 7.9%的患者出现症状性放射性坏死，与剂量无关。
在术后情况下，与低剂量 BED 方案相比，高剂量 FSRT（BED>37.5Gy）显著提高了局部控制率。总之，25Gy 5 次分割的剂量不足以控制微转移病灶。如果选择 5 次分割方案，30Gy 5 次分割似乎能很好地控制肿瘤床。
