Departments of1Radiation Oncology and.
2Radiation Physics, CNS/Pediatrics Section, The University of Texas MD Anderson Cancer Center, Houston.
J Neurosurg Spine. 2024 Jun 14;41(3):436-444. doi: 10.3171/2024.3.SPINE24157. Print 2024 Sep 1.
Variation exists in approaches to delivery of spine stereotactic radiosurgery (SSRS). Here, the authors describe outcomes following single-fraction SSRS performed using a simultaneous integrated boost for the treatment of prostate cancer spine metastases.
Health records of patients with prostate cancer spine metastases treated with single-fraction SSRS at the authors' institution were reviewed. Treatment was uniform, with 16 Gy to the clinical tumor volume and 18 Gy to the gross tumor volume. The primary endpoint was local recurrence, with secondary endpoints including vertebral fracture and overall survival. Univariate and multivariate competing risk regression models made using the Fine and Gray method were used to identify factors predictive of local recurrence, considering death to be a competing event for local recurrence.
A total of 87 targets involving 108 vertebrae in 68 patients were included, with a median follow-up of 22.5 months per treated target. The 1-, 2-, and 4-year cumulative incidence rates of local failure for all targets were 4.6%, 8.4%, and 19%, respectively. The presence of epidural disease (subdistribution hazard ratio [sHR] 5.43, p = 0.04) and SSRS as reirradiation (sHR 16.5, p = 0.02) emerged as significant predictors of local failure in a multivariate model. Hormone sensitivity did not predict local control. Vertebral fracture incidence rates leading to symptoms or requiring intervention at 1, 2, and 4 years were 1.1%, 3.7%, and 8.4%, respectively. In an exploratory analysis of patterns of failure, 3 (25%) failures occurred in the epidural space and only 1 (8%) occurred clearly in the clinical tumor volume. There were several lesions for which the precise location of failure with regard to target volumes was unclear.
High rates of local control were observed, particularly for radiotherapy-naïve lesions without epidural disease. Hormone sensitivity was not predictive of local control in this cohort and fracture risk was low. Further research is needed to better predict which patients are at high risk of recurrence and who might benefit from treatment escalation.
脊柱立体定向放射外科（SSRS）的实施方法存在差异。在此，作者描述了使用同步整合增敏单次分割 SSRS 治疗前列腺癌脊柱转移瘤的结果。
回顾了作者所在机构接受单次分割 SSRS 治疗的前列腺癌脊柱转移患者的健康记录。治疗方法统一，临床肿瘤体积给予 16Gy，大体肿瘤体积给予 18Gy。主要终点是局部复发，次要终点包括椎体骨折和总生存率。使用 Fine 和 Gray 方法的单变量和多变量竞争风险回归模型，将死亡视为局部复发的竞争事件，用于确定局部复发的预测因素。
共纳入 68 例患者的 87 个靶区，108 个椎体，每个治疗靶区的中位随访时间为 22.5 个月。所有靶区的 1、2 和 4 年局部失败累积发生率分别为 4.6%、8.4%和 19%。硬膜外疾病的存在（亚分布危险比[sHR]5.43，p=0.04）和 SSRS 作为再放疗（sHR 16.5，p=0.02）是多变量模型中局部失败的显著预测因素。激素敏感性不能预测局部控制。1、2 和 4 年导致症状或需要干预的椎体骨折发生率分别为 1.1%、3.7%和 8.4%。在失败模式的探索性分析中，3 例（25%）失败发生在硬膜外间隙，仅 1 例（8%）明显发生在临床肿瘤体积内。有几个病变的失败部位与靶区的位置不太明确。
观察到较高的局部控制率，尤其是对于无硬膜外疾病的放疗初治病变。在该队列中，激素敏感性不能预测局部控制，骨折风险较低。需要进一步研究以更好地预测哪些患者复发风险高，哪些患者可能受益于治疗升级。
