Park Younghee, Kim Hee Jung, Chang Ah Ram
Department of Radiation Oncology/CyberKnife Center, Soonchunhyang University Seoul Hospital, 59 Daesagwan-ro, Yongsan-gu, Seoul, 140-743, Republic of Korea.
Radiat Oncol. 2017 Apr 5;12(1):66. doi: 10.1186/s13014-017-0803-2.
To evaluate the incidence of chest wall toxicity after lung stereotactic ablative radiotherapy (SABR) and identify risk factors for the development of rib fracture.
Thirty-nine patients with 49 lesions underwent SABR for primary or metastatic lung tumors using Cyberknife® with tumor tracking systems. Patient characteristics, treatment factors and variables obtained from dose-volume histograms (DVHs) were analyzed to find the association with chest wall toxicity. Four-dimensional (4D) dose calculations were done to investigate the effect of respiratory motion on dose to the ribs.
After follow-up of median 26.7 months (range: 8.4 - 80.0), 8 patients (20.5%) experienced rib fractures and among these patients, three (37.5%) had chest wall pain at 2-3 months after SABR. Median time to rib fracture was 13.4 months (range: 8.0 - 38.5) and the 2-year actuarial risk of rib fracture was 12.2%. Dose to the 4.6 cc of the ribs (D) and rib volume received 160 Gy or more (V) were significant predictor for rib fracture. No significant differences between three-dimensional (3D) and 4D dose calculations were found.
Parameters from DVH are useful in predicting the risk of chest wall toxicity after SABR for lung tumors. Efforts should be made to reduce the risk of the rib fracture after lung SABR.
评估肺部立体定向消融放疗（SABR）后胸壁毒性的发生率，并确定肋骨骨折发生的危险因素。
39例患者共49个病灶接受了使用带有肿瘤追踪系统的赛博刀®进行的原发性或转移性肺肿瘤SABR治疗。分析患者特征、治疗因素以及从剂量体积直方图（DVH）获得的变量，以寻找与胸壁毒性的关联。进行四维（4D）剂量计算，以研究呼吸运动对肋骨剂量的影响。
中位随访26.7个月（范围：8.4 - 80.0个月）后，8例患者（20.5%）发生肋骨骨折，其中3例（37.5%）在SABR后2 - 3个月出现胸壁疼痛。肋骨骨折的中位时间为13.4个月（范围：8.0 - 38.5个月），2年肋骨骨折精算风险为12.2%。肋骨4.6 cc的剂量（D）和接受160 Gy或更高剂量的肋骨体积（V）是肋骨骨折的显著预测因素。三维（3D）和4D剂量计算之间未发现显著差异。
DVH参数有助于预测肺部肿瘤SABR后胸壁毒性的风险。应努力降低肺部SABR后肋骨骨折的风险。
