Study on the Effect of Different Bladder Filling Volume on Target Area and Organs at Risk during Three-Dimensional Brachytherapy for Postoperative Early Cervical Cancer

Abstract

<h3>Purpose/Objective(s)</h3> To investigate the optimal bladder filling volume in the 3D brachytherapy of postoperative cervical cancer. <h3>Materials/Methods</h3> Patients of early cervical cancer with a positive incisal margin or insufficient safety boundary were included. 50ml, 60ml, 70ml, 80ml, 90ml, and 100ml of normal saline were randomly filled into their bladders. There was a total of 6 groups. The CT simulation positioning was performed. According to ICRU89 report, high-risk clinical target volume, bladder, rectum, and other organs at risk were delineated. The radiotherapy treatment planning system was used to make the treatment plan. The volume of HR-CTV, D90, and D2cc and D1cc of organs at risk under different volumes were recorded respectively. <h3>Results</h3> A total of 111 patients were enrolled and there were 398 person-times of 3D brachytherapy treatment program were performed. Among them, there were 66 person-times in the 50ml group, 69 person-times in the 60ml group, 66 person-times in the 70ml group, 69 person-times in the 80ml group, 72 person-times in the 90ml group, and 56 person-times in the 100ml group. Compared with the 60ml group, the volume and dosage of HR-CTV in the groups of 50ml, 70ml, 80ml, 90ml, and 100ml had no significant difference (P>0.05), D2cc and D1cc of the bladder and rectum significantly decreased, the difference was statistically significant (P<0.05). Pairwise comparison between other 5 groups, the volume and dosage of HR-CTV, D2cc and D1cc of bladder and rectum had no significant difference (P>0.05). <h3>Conclusion</h3> In the 3D brachytherapy of postoperative early cervical cancer, compared with other volumes, the bladder perfusion of 60ml can ensure the volume and dose of HR-CTV and reduce better the dose of the bladder and rectum.