Reduction of rectal toxicity in prostate cancer radiation therapy by implantable rectum spacers

This dissertation examines how to minimise gastrointestinal side effects of external prostate cancer radiation therapy by using a rectum spacer (a balloon that shifts the rectum away from the prostate). The rectum spacer is used to increase the space between rectum and prostate, therefore pushing the rectum out of the irradiated area. As a result, patients with prostate cancer suffer less gastrointestinal irritation, including symptoms of diarrhoea, constipation, mucous secretion, cramps and increased frequency of defaecation, faecal urgency or faecal incontinence. Various aspects of the rectum spacer were studied: cost-effectiveness, planning studies (comparative treatments with and without rectum spacer), selection of patients who may benefit most from this method, and the first implants in patients with prostate cancer and Crohn’s disease. Finally, we examined the personalisation of radiation doses by implanting a rectum spacer, i.e. safely increasing radiation doses with a higher chance of cure but without producing more side effects.