Mitsuyoshi Takamasa, Tokuda Peter J K, Kokubo Yumi, Iwai Takahiro, Inoo Hiroyuki, Ashida Ryo, Nasada Ryosuke, Yamashita Mikiko, Tanabe Hiroaki, Arizono Shigeki, Imagumbai Toshiyuki, Kokubo Masaki
Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Japan.
Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Adv Radiat Oncol. 2025 Apr 25;10(6):101760. doi: 10.1016/j.adro.2025.101760. eCollection 2025 Jun.
Stereotactic body radiation therapy (SBRT) is an effective treatment approach for spinal metastases. However, local recurrence may occur. This prospective phase 2 trial evaluated whether SBRT with dose escalation in the gross tumor volume through simultaneous integrated boost (SIB-SBRT) can improve local control (LC) without increasing adverse events (AEs).
Eligible patients aged ≥ 20 years with spinal metastases and a life expectancy of > 1 year received SIB-SBRT in 5 fractions over 1 week. The prescribed dose was 30 Gy to the planning target volume for evaluation and an escalated dose of 40 to 45 Gy to the gross tumor volume through SIB. Neurologic examinations and magnetic resonance imaging were performed at 3-, 6-, and 12-month follow-up and every 6 months thereafter. The primary endpoint was the 1-year LC rate. The secondary endpoints included overall survival and AEs, such as vertebral compression fractures (VCFs).
A total of 25 patients with 28 vertebral segments from September 2020 to March 2023 were enrolled in this study. The median follow-up was 26.2 months, and 24 segments in 21 patients were followed up for >1 year. The 1- and 2-year LC rates were 100.0% and 95.0%, respectively. Local recurrence developed in only 1 patient at 18 months. The 1- and 2-year overall survival rates were 92.0% and 72.8%, respectively. Six patients developed VCFs (3 cases each of grades 1 and 2), with 1- and 2-year cumulative incidence rates of 3.6% and 15.6%, respectively. No radiation myelopathy or other grade ≥ 2 AEs occurred, except for 1 case of grade 2 pain.
Dose-escalated SIB-SBRT for spinal metastases demonstrates excellent LC with acceptable toxicity, supporting the need for a larger comparative trial.
立体定向体部放射治疗（SBRT）是脊柱转移瘤的一种有效治疗方法。然而，可能会发生局部复发。这项前瞻性2期试验评估了通过同步整合加量（SIB-SBRT）在大体肿瘤体积中进行剂量递增的SBRT是否能在不增加不良事件（AE）的情况下改善局部控制（LC）。
年龄≥20岁、患有脊柱转移瘤且预期寿命>1年的符合条件的患者在1周内分5次接受SIB-SBRT。计划靶体积的处方剂量为30 Gy用于评估，通过SIB将大体肿瘤体积的剂量递增至40至45 Gy。在3个月、6个月和12个月的随访时以及此后每6个月进行神经系统检查和磁共振成像。主要终点是1年局部控制率。次要终点包括总生存期和AE，如椎体压缩骨折（VCF）。
2020年9月至2023年3月，共有25例患者的28个椎体节段纳入本研究。中位随访时间为26.2个月，21例患者的24个节段随访时间>1年。1年和2年局部控制率分别为100.0%和95.0%。仅1例患者在18个月时出现局部复发。1年和2年总生存率分别为92.0%和72.8%。6例患者发生VCF（1级和2级各3例），1年和2年累积发生率分别为3.6%和15.6%。除1例2级疼痛外，未发生放射性脊髓病或其他≥2级AE。
剂量递增的SIB-SBRT治疗脊柱转移瘤显示出优异的局部控制效果且毒性可接受，支持开展更大规模的对比试验。
