%D 2023
%P 1-298
%T Optimisation of cervical cancer radiotherapy  with a focus on improving the therapeutic ratio  and reducing ureter toxicity
%A Asma Sarwar
%O Copyright © The Author 2023.  Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/).  Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms.  Access may initially be restricted at the author’s request.
%X Optimal treatment of locally advanced cervical cancer involves chemo radiation and image guided 
brachytherapy. Technological advances with image guidance have improved the therapeutic ratio, 
enabling more accurate dose delivery to the target volume and sparing organs at risk. Achieving doses 
of > 85Gy to the high-risk clinical target volume results in 3-year local control rates of 86-94%. Strict 
planning criteria for organs at risk are established to prevent long term toxicity and morbidity. Ureters 
are a structure in the pelvis in close relation to the cervix which are not routinely contoured as organs 
at risk, doses are not recorded, and no optimization constraints exist despite the significant risk of 
radiation induced ureteric stenosis.
To date very little cohesive data exist on the effect of radiation to the ureters during radical 
radiotherapy for cervical cancer. I have performed a comprehensive systematic review to summarise 
the existing data on this subject and to identify important risk factors. I have also produced a step by 
step pictorial atlas in conjunction with gynae radiologists to aid ureter identification and delineation 
and assessed its use. Once a method for contouring ureters was established, I retrospectively 
contoured ureters on brachytherapy MRI images to allow a novel dosimetric analysis of dose to ureters 
during cervical brachytherapy. I also investigated the feasibility of ureter dose optimisation during 
cervical brachytherapy. Finally, I assessed the dose to ureters and other organs at risk during RapidArc 
external beam radiotherapy and proton beam therapy, to establish if any therapeutic advantages can 
be gained.
%L discovery10166324
%I UCL (University College London)