Zhang Ning, Liu Ying, Han Dongmei, Guo Xin, Mao Zhuang, Yang Wei, Cheng Guanghui
Department of Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
Front Oncol. 2021 Jul 23;11:693864. doi: 10.3389/fonc.2021.693864. eCollection 2021.
To establish a dose volume-effect relationship for predicting late rectal complication (LRC) in locally advanced cervical cancer patients treated with external beam radiotherapy (EBRT) followed by combined intracavitary/interstitial brachytherapy (IC/IS-BT).
A retrospective analysis was performed in 110 patients with locally advanced cervical cancer who underwent definitive radiotherapy combined with IC/IS-BT from July 2010 to September 2018. We report the 90% of the target volume receiving the minimum dose for high risk clinical target volume (HR-CTV D) and intermediate risk clinical target volume (IR-CTV D), and the minimum doses to the most exposed 0.1, 1, and 2 cm³ doses at the International Commission on Radiation Units and Measurements (D) for organs at risk (OARs). The total dose of EBRT plus brachytherapy was transformed to the biologically equivalent dose in 2 Gy fractions (EQD2) with α/β value of 10 Gy for target, 3 Gy for organs at risk using the linear quadratic model. The morbidity was scored according to the Radiation Therapy Oncology Group (RTOG) criteria. The Probit model was used to establish a prediction model on rectum between the organs at risk for dose and LRC. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of dose volume parameters for LRC.
The median follow-up time was 72.3 months. The mean ( ± standard deviation) , and D values of rectum were 64.72 ± 7.47 Gy, 70.18 ± 5.92 Gy, 79.32 ± 7.86 Gy, and 67.22 ± 7.87 Gy, respectively. The Probit model showed significant relationships between , and the probability of grade1-4, grade 2-4 rectal events at 1 year, and between and the probability of grade2-4 rectal events at 3 and 5 years. The dose values for 10% complication rates (ED10) of were 74.18 (70.42-76.71) Gy, 67.80 (59.91, 71.08) Gy, 66.37 (52.00, 70.27) Gy for grade 2-4 with rectal morbidity at 1, 3, and 5 years, respectively.
Our study proved that were considered as useful dosimetric parameters for predicting the risk of grade1-4 and grade2-4 LRC at 1-year, and might be an indicator for predicting grade2-4 LRC at 3/5years. The patients with rectal >66.37-74.18 Gy should be closely observed for grade2-4 LRC.
建立剂量体积效应关系，以预测接受体外放射治疗（EBRT）后联合腔内/组织间近距离放射治疗（IC/IS-BT）的局部晚期宫颈癌患者的晚期直肠并发症（LRC）。
对2010年7月至2018年9月期间接受确定性放疗联合IC/IS-BT的110例局部晚期宫颈癌患者进行回顾性分析。我们报告高危临床靶区（HR-CTV D）和中危临床靶区（IR-CTV D）接受最小剂量的90%靶体积，以及国际辐射单位与测量委员会（ICRU）规定的危及器官（OARs）中最易受照射的0.1、1和2 cm³剂量处的最小剂量。使用线性二次模型将EBRT加近距离放射治疗的总剂量转换为生物等效剂量（EQD2），靶区的α/β值为10 Gy，危及器官的α/β值为3 Gy。根据放射治疗肿瘤学组（RTOG）标准对发病率进行评分。使用Probit模型建立危及器官剂量与LRC之间直肠的预测模型。采用受试者操作特征（ROC）曲线评估剂量体积参数对LRC的预测价值。
中位随访时间为72.3个月。直肠的平均（±标准差） 、D值分别为64.72±7.47 Gy、70.18±5.92 Gy、79.32±7.86 Gy和67.22±7.87 Gy。Probit模型显示， 与1年时1-4级、2-4级直肠事件的概率之间，以及 与3年和5年时2-4级直肠事件的概率之间存在显著关系。1年、3年和5年时2-4级直肠发病率的10%并发症发生率（ED10）的剂量值分别为74.18（70.42-76.71）Gy、67.80（59.91，71.08）Gy、66.37（52.00，70.27）Gy。
我们的研究证明， 被认为是预测1年时1-4级和2-4级LRC风险的有用剂量学参数， 可能是预测3/5年时2-4级LRC的指标。直肠 >66.37-74.18 Gy的患者应密切观察2-4级LRC。
