多发性骨髓瘤（MM）常规外束放射治疗（cEBRT）用于治疗严重疼痛、脊髓压迫和与疾病相关的骨病。然而，放射治疗可能与椎体压缩骨折（VCFs）的风险增加相关，这可能会严重影响生存和生活质量。此外，MM中使用脊柱不稳定恶性肿瘤评分（SINS）在MM中存在争议。目的是确定MM患者接受cEBRT后VCFs的发生率，并评估SINS评分在MM预测VCFs中的适用性。方法：回顾性多中心队列研究。研究对象为在2010年1月至2021年12月期间接受cEBRT治疗的MM患者。主要观察指标为新型或进展的VCFs的频率和潜在相关因素的子分布风险比。从患者电子病历手动收集患者和治疗特征。使用治疗开始前和治疗开始后3年内的计算机断层扫描（CT）图像评分基线和随访。进行多变量危险模型分析以评估SINS评分对预测放射后VCF率的诊断价值。结果：本研究共纳入127例患者，包括427个符合条件的射线化椎体。放射治疗时的平均年龄为64岁，其中66.1%为男性。放射治疗开始时，57例患者（44.9%）至少有一个VCF。现有的VCFs中有89个（占483个椎体的18.4%）。总体上，39名患者中的30.7%报告了新的骨折（椎体数（n）= 12）或现有骨折的进展（n = 36）。这个数字代表了所有放射椎体的11.2%。39名出现新或恶化VCFs的患者中，有5名（12.8%）在三年内接受了计划外的二次治疗（增强（n = 2）或开放手术（n = 3））。在调整分析中，总SINS评分（SHR 1.77；95%置信区间（CI）1.54 - 2.03；p < .001）和分类SINS评分（SHR 10.83；95% CI 4.20 - 27.94；p < .001）均独立与新的或进展的VCFs率呈正相关。双磷酸盐的使用与新的或进展的VCFs率呈负相关（SHR 0.47；95% CI 0.24 - 0.92；p = .027）。本研究表明，三年内有30.7%的患者出现了新的或进展的VCFs，椎体总数为11.2%。SINS评分与VCFs的发生或进展显著相关，因此在MM中可应用于骨折的预测和可能的预防。Copyright © 2023. Elsevier Inc.出版。

Conventional external beam radiation therapy (cEBRT) is used in multiple myeloma (MM) to treat severe pain, spinal cord compression, and disease-related bone disease. However, radiation may be associated with an increased risk of vertebral compression fractures (VCFs), which could substantially impair survival and quality of life. Additionally, the use of the Spinal Instability Neoplastic Score (SINS) in MM is debated in MM.To determine the incidence of VCFs after cEBRT in patients with MM and to assess the applicability of the SINS score in the prediction of VCFs in MM.Retrospective multicenter cohort study.MM patients with spinal myeloma lesions who underwent cEBRT between January 2010 and December 2021.Frequency of new or progressed VCFs and subdistribution hazard ratios for potentially associated factors.Patient and treatment characteristics were manually collected from the patients' electronic medical records. Computed tomography (CT) scans from before and up to 3 years after the start of radiation were used to score radiographic variables at baseline and at follow-up. Multivariable Fine and Gray competing risk analyses were performed to evaluate the diagnostic value of the SINS score to predict the post-radiation VCF rate.A total of 127 patients with 427 eligible radiated vertebrae were included in this study. The mean age at radiation was 64 years, and 66.1% of them were male. At the start of radiation, 57 patients (44.9%) had at least one VCF. There were 89 pre-existing VCFs (18.4% of 483 vertebrae). Overall, 39 of 127 patients (30.7%) reported new fractures (number of vertebrae (n) = 12) or showed progression of existing fractures (n = 36). This number represented 11.2% of all radiated vertebrae. Five of the 39 (12.8%) patients with new or worsened VCFs received an unplanned secondary treatment (augmentation (n = 2) or open surgery (n = 3)) within three years. Both the total SINS score (SHR 1.77; 95% confidence interval (CI) 1.54 - 2.03; p < .001) and categorical SINS score (SHR 10.83; 95% CI 4.20 - 27.94; p < .001) showed an independent association with higher rates of new or progressed VCFs in adjusted analyses. The use of bisphosphonates was independently associated with a lower rate of new or progressed VCFs (SHR 0.47 (95% CI 0.24 - 0.92; p = .027)).This study demonstrated that new or progressed VCFs occurred in 30.7% of patients within three years, in a total of 11.2% of vertebrae. The SINS score was found to be independently associated with the development or progression of VCFs and could thus be applied in MM for fracture prediction and possibly prevention.Copyright © 2023. Published by Elsevier Inc.