Purpose: The optimal method for the second course of stereotactic body radiotherapy (SBRT) for spinal metastases remains poorly established. This single-center, single-arm, phase II trial was conducted to propose a safe and effective salvage spine SBRT. Methods: The patients initially treated with SBRT for spine-targeted protocol treatment, or for areas adjacent to the spine, were enrolled. The second SBRT dose was 30 Gy delivered in five fractions; the spinal cord dose constraint was 15.5 Gy at the maximum point dose. The brachial or lumbosacral plexuses were dose-constrained to <30 Gy if the boundary between the nerves and tumors was detected. The primary endpoint was dose-limiting toxicity (DLT) (grade ≥ 3 severe radiation-related toxicity) within a year after the second SBRT. Results: The second SBRT was administered to the same spinal level in 12 patients and to an adjacent spinal level in 8 patients. SBRT2 was performed for 14 painful lesions, 10 MESCC, and 6 oligometastases, with some lesions having multiple indications. The median interval between SBRT sessions was 21 months (range: 6–51 months). The median follow-up duration was 14 months. No radiation myelopathy or local failure was reported during the follow-up period. DLT was confirmed in two patients (10%) within a year, both of whom developed grade 3 lumbosacral plexopathy. These two patients received SBRT twice to the S1–2 and S1–5 vertebrae, respectively, and both experienced paralysis of the tibialis anterior muscle (L5 level). Grade 3 late adverse effects (including lumbosacral plexopathy and vertebral compression fracture) were observed in 25% of the patients throughout the entire follow-up period. Conclusions: The second spine SBRT achieved good local control without causing myelopathy. However, one-quarter of the patients experienced grade 3 late adverse effects, suggesting that the treatment protocol carries a risk of toxicity.
目的：针对脊柱转移瘤的第二次立体定向放射治疗（SBRT）的最佳方案尚未明确。本研究通过一项单中心、单臂、II期临床试验，旨在提出一种安全有效的挽救性脊柱SBRT方案。方法：纳入既往因脊柱靶区或邻近区域接受过SBRT治疗的患者。第二次SBRT剂量为30 Gy，分5次照射；脊髓最大点剂量限制为15.5 Gy。若神经与肿瘤边界可辨，臂丛或腰骶丛神经剂量限制需＜30 Gy。主要终点为第二次SBRT后一年内发生的剂量限制性毒性（DLT）（≥3级严重放射相关毒性）。结果：20例患者中，12例在同一脊柱节段、8例在相邻脊柱节段接受第二次SBRT。治疗指征包括14处疼痛性病灶、10处转移性硬膜外脊髓压迫和6处寡转移灶（部分病灶存在多重指征）。两次SBRT治疗中位间隔时间为21个月（范围：6-51个月）。中位随访时间为14个月。随访期间未出现放射性脊髓病或局部治疗失败。一年内确认2例患者（10%）发生DLT，均为3级腰骶丛神经病变。此2例患者分别于S1-2和S1-5椎体接受两次SBRT，均出现胫骨前肌麻痹（L5水平）。整个随访期间，25%的患者出现3级晚期不良反应（包括腰骶丛神经病变和椎体压缩性骨折）。结论：第二次脊柱SBRT实现了良好的局部控制且未引发脊髓病变，但四分之一患者出现3级晚期不良反应，提示该治疗方案存在毒性风险。
Phase II Clinical Trial of Second Course of Stereotactic Body Radiotherapy for Spinal Metastases
肿瘤(癌症)患者之家