Can Bladder Late Complications be predicted in Cervical Cancer HDR Brachytherapy?

Purpose: Multi-fraction high-dose-rate (HDR) brachytherapy (BT) is an important element in the treatment regimen for locally advanced carcinoma of cervix. While standard treatment planning guidelines have been established for dose-volume-histogram (DVH) based thresholds for the surrounding organs at risk (OAR), there are still high-grade complications observed in these OAR that cannot be explained by the traditional DVH parameters. In our centre, the practice of changing the bladder volume between fractions has been applied with the aim of reducing toxicity by shifting the location of high-dose regions on the bladder from fraction to fraction. In this study, we investigate the effectiveness of this practice, as well as the correlation of bladder toxicity with selected non-dosimetric parameters and bladder neck accumulated dose.