A comparison between 2D and 3D planning of high-dose-rate vaginal cuff brachytherapy in patients with stage I-II endometrial cancer using cobalt-60.

Abstract

PurposePost-surgery radiation can reduce the risk of loco-regional relapse in high-intermediate-risk endometrial cancer. High-dose-rate vaginal cuff brachytherapy (HDR-BRT) is an acceptable method of radiation in majority of endometrial cancer cases. Although 2D planning is frequently used for treatment based on physical examination without any imaging, measurement of the dose received by organs-at-risk (OARs) is not possible. Therefore, the present study was the first to compare dose delivered to target and OARs in 2D vs. 3D planning in patients treated with cobalt-60 source.Material and methodsIn this study, organs including vagina wall, bladder, rectum, and sigmoid were contoured on computed tomography (CT) scan images of 37 endometrial cancer patients, and doses delivered to organs were recorded. Statistics, such as D90, D99, V100, V150, V200, D0.1cc, D1cc, and D2cc were determined.ResultsD90 and D99 were lower in 3D treatment planning in comparison with 2D. Although V100 was more in 3D planning, V150 and V200 were less. Analyzing D0.1cc, D1cc, and D2cc of OARs revealed that doses given to rectum, sigmoid, and bladder were less in 3D planning compared to 2D.ConclusionsComparison of 2D and 3D planning results showed that 3D planning could deliver an appropriate dose to the target while sparing more OARs.