Senkus-Konefka E, Kobierska A, Jassem J, Badzio A
Department of Oncology and Radiotherapy, Medical University of Gdańsk,Poland.
Int J Radiat Oncol Biol Phys. 1997 Feb 1;37(3):531-6. doi: 10.1016/s0360-3016(96)00561-5.
The aim of this study was to assess retrospectively the influence of the size of cervical cancer brachytherapy applicators (ovoids and uterine tandems) on pelvic dose distribution and to analyze the impact of various patient- and disease-related factors on applicators' geometry and on dose distribution in particular applications.
The subject of this study were 356 cervical cancer patients treated with Selectron LDR as a part of their radical radiotherapy. Analyzed factors included patient age, weight, number of vaginal deliveries, and disease stage.
The use of larger vaginal applicators resulted in lower bladder and rectum doses and in higher point B doses (all p < 0.0001); longer uterine tandems produced lower rectum doses and higher point B doses (both p < 0.0001). Increasing patient age and disease stage resulted in a decreased frequency of use of large ovoids (both p < 0.0001) and of long tandems (age: p = 0.0069, stage: p = 0.004). As a result, higher doses to bladder (age: p < 0.0001, stage: p = 0.017) and rectum (age: p = 0.037, stage: p = 0.011) were observed. Increasing age also resulted in lower point B doses (p < 0.0001). Increasing patient weight correlated with less frequent use of long tandems (p = 0.0015) and with higher bladder doses (p = 0.04). Higher number of vaginal deliveries was related to the increase in the use of long tandems (p = 0.002); in patients who had had at least one vaginal delivery, point B doses were significantly higher (p = 0.0059). In multivariate analysis ovoid size and uterine tandem length were dependent on patient age (respectively: p < 0.001 and p = 0.001), disease stage (respectively: p = 0.003 and p = 0.008) and on the number of vaginal deliveries (respectively: p = 0.07 and p = 0.008). Doses to critical organs and to points B were dependent on patient age (respectively: p < 0.001, p = 0.011, and p < 0.001) and on disease stage (respectively: p < 0.001, p = 0.004, and p = 0.048).
The results of this study allow for identification of some patient- and disease-related factors influencing pelvic dose distribution in cervical cancer brachytherapy. This potentially may enable optimization of the dose distribution in particular clinical situations.
本研究的目的是回顾性评估宫颈癌近距离放疗施源器（卵圆体和子宫施源器）的尺寸对盆腔剂量分布的影响，并分析各种患者和疾病相关因素对施源器几何形状以及特定应用中剂量分布的影响。
本研究的对象是356例接受Selectron LDR作为根治性放疗一部分的宫颈癌患者。分析的因素包括患者年龄、体重、阴道分娩次数和疾病分期。
使用较大的阴道施源器会导致膀胱和直肠剂量降低，B点剂量升高（所有p<0.0001）；较长的子宫施源器会使直肠剂量降低，B点剂量升高（两者p<0.0001）。患者年龄和疾病分期增加会导致大卵圆体（两者p<0.0001）和长施源器（年龄：p=0.0069，分期：p=0.004）的使用频率降低。结果，观察到膀胱（年龄：p<0.0001，分期：p=0.017）和直肠（年龄：p=0.037，分期：p=0.011）接受的剂量更高。年龄增加还会导致B点剂量降低（p<0.0001）。患者体重增加与长施源器使用频率降低（p=0.0015）和膀胱剂量升高（p=0.04）相关。阴道分娩次数增加与长施源器使用增加有关（p=0.002）；在至少有一次阴道分娩的患者中，B点剂量显著更高（p=0.0059）。多因素分析显示，卵圆体尺寸和子宫施源器长度取决于患者年龄（分别为：p<0.001和p=0.001）、疾病分期（分别为：p=0.003和p=0.008）以及阴道分娩次数（分别为：p=0.07和p=0.008）。关键器官和B点的剂量取决于患者年龄（分别为：p<0.001、p=0.011和p<0.001）和疾病分期（分别为：p<0.001、p=0.004和p=0.048）。
本研究结果有助于识别一些影响宫颈癌近距离放疗盆腔剂量分布的患者和疾病相关因素。这可能有助于在特定临床情况下优化剂量分布。
