Tsai Yu-Lun, Yu Pei-Chieh, Nien Hsin-Hua, Sung Shih-Yu, Kuan Yi-Hsuan, Wu Ching-Jung
Department of Radiation Oncology, Cathay General Hospital, Taipei, Taiwan.
Department of Radiation Oncology, Cathay General Hospital, Taipei, Taiwan; School of Medicine, China Medical University, Taichung, Taiwan.
Med Dosim. 2019;44(4):e59-e63. doi: 10.1016/j.meddos.2019.01.006. Epub 2019 Mar 4.
Cervical cancer patients may sometimes experience different types of uterine perforation by a tandem during brachytherapy. The purpose of this study was to address possibly different management strategies regarding different tandem positions from a dosimetry aspect by evaluating radiation doses delivered to organs-at-risk (OAR) in order to help medical professionals handle different types of uterine perforation. Images and dosimetry data in cervical cancer brachytherapy with uterine perforation were reviewed. Uterine perforation was classified into anterior and posterior perforation according to their tandem positions. Radiation doses received by OAR, including D and D of the bladder, rectum, and sigmoid colon, were statistically compared with nonperforation. The doses of high-risk clinical target volume (HR-CTV) of cervical tumor and bilateral point A were also compared in order to assure that the plans had not compromised the treatment efficacy. A total of 21 applications were assessed, including 5 with anterior perforation, 4 with posterior perforation, and 12 without perforation. In anterior perforation, the bladder was the only organ that received a significantly increased dose about 30% at D and D. However, in posterior perforation, multiple OAR received significantly excessive doses: approximately 30% for the bladder, 37% for the rectum, and 100% for the sigmoid colon. The OAR dose assessment was based on a statistically equivalent cervical tumor dose. Different management strategies are possible for anterior vs posterior perforation during brachytherapy due to different detrimental extents on OAR dosimetry. The bladder warrants more attention in anterior perforation, without compromising target coverage in treatment planning. On the other hand, repositioning may be considered in posterior perforation due to relatively massive OAR detriments. This concept is a new one and is given for the first time.
宫颈癌患者在近距离放射治疗期间，有时可能会因施源器发生不同类型的子宫穿孔。本研究的目的是通过评估危及器官（OAR）所接受的辐射剂量，从剂量学角度探讨针对不同施源器位置可能采取的不同管理策略，以帮助医学专业人员处理不同类型的子宫穿孔。回顾了宫颈癌近距离放射治疗中发生子宫穿孔的图像和剂量学数据。根据施源器位置，将子宫穿孔分为前穿孔和后穿孔。对膀胱、直肠和乙状结肠等OAR所接受的辐射剂量（包括D和D）与未穿孔情况进行统计学比较。还比较了宫颈肿瘤高危临床靶区（HR-CTV）和双侧A点的剂量，以确保治疗计划未损害治疗效果。共评估了21例应用情况，包括5例前穿孔、4例后穿孔和12例未穿孔。在前穿孔中，膀胱是唯一在D和D时剂量显著增加约30%的器官。然而，在后穿孔中，多个OAR接受了明显过量的剂量：膀胱约30%、直肠37%、乙状结肠100%。OAR剂量评估基于统计学等效的宫颈肿瘤剂量。由于对OAR剂量学的有害程度不同，近距离放射治疗期间前穿孔和后穿孔可能需要采取不同的管理策略。在前穿孔中，膀胱需要更多关注，同时在治疗计划中不影响靶区覆盖。另一方面，由于OAR损害相对较大，后穿孔可能需要考虑重新定位。这一概念是全新的，首次提出。
