Reducing small bowel toxicity in locally advanced cervical cancer treatment

This thesis presents results that aim to provide new solutions to improve the results of radiotherapy in women with locally advanced cervical cancer. These proposed solutions mainly focused on techniques to reduce severe late toxicity after chemoradiotherapy by reducing the radiation dose to healthy organs at risk, particularly to the small bowel. First, the thesis provides an overview of current practice in the Netherlands in Part I. Then, in Part II provides results of validating MRI for craniocaudal tumour measurements in cervical cancer in a systematic review, retrospective and prospective studies. Part III presents results of reducing small bowel toxicity by changing radiotherapy strategies, by:
- Using proton therapy compared to with photon therapy using an image-guided adaptive radiotherapy with a plan of the day strategy.
- Using daily online MRI-based replanning compared to image-guided adaptive radiotherapy with a plan of the day strategy.
- Excluding uninvaded uterine tissue out of elective treatment volumes compared to not excluding these parts.
In summary, underestimation of cervical craniocaudal tumour size on MRI is within 10 mm. Patients with small tumours and a substantial part of the small bowel near target volumes, will most likely benefit from an approach in which the uninvaded uterus is lowered in elective EBRT target volumes, and/or an approach in which proton beam therapy and/or online replanning are used. The use of either of these approaches allows a smaller dose to be delivered to OAR, in general particularly to the small bowel.