University of Melbourne, Melbourne, Victoria, Australia.
Genesis Cancer Care, Melbourne, Victoria, Australia; Austin Health, Heidelberg, Victoria, Australia.
Clin Oncol (R Coll Radiol). 2020 Jul;32(7):433-441. doi: 10.1016/j.clon.2020.02.030. Epub 2020 Mar 10.
Stereotactic body radiotherapy (SBRT) is a locally ablative therapy used for the treatment of patients with spine metastases. However, it is associated with higher rates of vertebral compression fractures (VCF) than conventionally fractionated palliative radiotherapy. The purpose of this study was to determine the rate of VCF following spine SBRT and to identify the risk factors associated with this outcome.
We retrospectively reviewed patients treated at two Australian institutions from January 2015 to March 2019. Descriptive statistics were used to assess patient, tumour and treatment factors. The Log-rank test and Cox proportional hazards model were applied in univariate and multivariable analyses to identify factors associated with VCF, local control and overall survival.
We evaluated 113 spinal segments from 84 patients, with a median follow-up time of 11.9 months. The median dose and fractionation utilised was 30 Gy in three fractions (67.3%), with a single-fraction rate of 0.9%. The median Spinal Instability Neoplastic Score (SINS) of the lesions was 4/18, with most (84.1%) being SINS stable, scoring between 0 and 6. Five VCFs were observed (three progression of pre-existing fractures and two de novo), a cumulative VCF risk of 4.4%. Four of five fractures occurred within the first year after treatment, with a median time to VCF of 9.2 months. A pre-existing VCF (P = 0.011) was associated with subsequent fracture on multivariable analysis, whereas all VCF segments displayed lytic disease appearance. All fractures were managed conservatively with analgesia, without requirement for subsequent surgical intervention.
SBRT to spine metastases is safe with respect to VCF, with rates around the lower limit observed in similar studies. Knowledge of factors that predispose to post-treatment fracture, such as pre-existing compression, lytic vertebral disease and SINS >6 will aid in the counselling and selection of patients for this therapy.
立体定向体部放疗（SBRT）是一种局部消融疗法，用于治疗脊柱转移瘤患者。然而，与常规分割姑息性放疗相比，SBRT 后脊柱压缩性骨折（VCF）的发生率更高。本研究旨在确定脊柱 SBRT 后 VCF 的发生率，并确定与该结果相关的危险因素。
我们回顾性分析了 2015 年 1 月至 2019 年 3 月在澳大利亚的两家机构接受治疗的患者。采用描述性统计评估患者、肿瘤和治疗因素。对数秩检验和 Cox 比例风险模型用于单因素和多因素分析，以确定与 VCF、局部控制和总生存相关的因素。
我们评估了 84 例患者的 113 个脊柱节段，中位随访时间为 11.9 个月。中位剂量和分割为 30Gy/3 次（67.3%），单次分割率为 0.9%。病变的中位脊柱不稳定肿瘤评分（SINS）为 4/18，其中大多数（84.1%）为 SINS 稳定，评分为 0-6 分。观察到 5 例 VCF（3 例为原有骨折进展，2 例为新发骨折），累积 VCF 风险为 4.4%。5 例骨折均发生在治疗后 1 年内，中位 VCF 时间为 9.2 个月。多因素分析显示，治疗前 VCF（P=0.011）与随后的骨折相关，而所有 VCF 节段均显示溶骨性疾病表现。所有骨折均采用镇痛保守治疗，无需进一步手术干预。
脊柱转移瘤 SBRT 治疗 VCF 是安全的，其发生率与类似研究中的下限相近。了解易发生治疗后骨折的危险因素，如治疗前存在的压缩、溶骨性椎体疾病和 SINS>6，将有助于为该治疗方法提供咨询和选择患者。
