乳腺癌术后逆向调强放疗致放射性肺损伤的剂量学研究

Dosimetric Study on Reverse Intensity-Modulated Radiotherapy Induced Radioactive Lung Damage in Patients with Breast Cancer

目的探讨乳腺癌改良根治术后逆向调强放疗剂量学指标与放射性肺损伤发生的关系。方法将接受逆向调强放疗治疗的113例女性乳腺癌患者分为发生肺损伤组和未发生肺损伤组,对年龄、肺气肿、慢性支气管炎等临床因素及肺相关的剂量学因素行单因素及多因素分析。结果中位随访27.5个月,放射性肺损伤发生率为15.9%(18/113)。单因素分析显示胸壁厚度、双肺接受5 Gy(V5)、10 Gy(V10)、13 Gy(V13)、15 Gy(V15)照射剂量的肺的体积百分比在发生肺损伤组明显高于未发生肺损伤组;多因素分析显示V10、V13是判断放射性肺损伤的独立预测因素。以V10<33%和V13<23%为分界点,对放射性肺损伤预测的敏感性分别为94.4%和94.4%,特异性分别为84.2%和80.0%。结论在逆向调强计划中,V10、V13是放射性肺损伤的较佳预测因子,逆向调强放疗中较小的剂量分散到较大的体积中也是不安全的。

Objective To investigate the dosimetric factors associated with radiation -induced lung damage in pa- tients with breast cancer treated by reverse intensity -modulated radiotherapy. Methods 113 breast cancer patients who under- went reverse intensity - modulated radiotherapy were divided into lung damage group and non - lung damage group. Several clini- cal factors including age, emphysema, chronic bronchitis and dosimetric factors were analyzed by univariate and multivariate logis-tic regression analysis. Results The median follow - up time was 27.5 months. The incidence of radiation - induced lung dam- age was 15.9%. Univariate analysis showed that the thickness of chest wall, V5 , V10, V13, Vl5, mean lung dose （MLD） were all significantly higher in lung damage group than those in non - lung damage group （ P 〈 0. 05 ） . Multivariate analysis showedthat Vl0 and Vl3 were independent factors for radiation -induced lung damage. When using Vlo 〈 33% as a cut -off to predict ra- diation - induced lung damage, the sensitivity and specificity were 94.4% and 84. 2%. When using V13 〈23% as a cut - off to predict radiation - induced lung damage, the sensitivity and specificity were 94.4% and 80. 0%. Conclusion V10 and V13 arevaluable indicators for predicting radiation - induced lung damage. In reverse intensity - modulated radiotherapy, it is not safe to spread small dose of radiation to a larger body.