ESTRO 2023 - Abstract Book

S1128

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ESTRO 2023

Figure 1:

Conclusion Physician assessed and patient reported bladder morbidity was generally low after long course radio(chemo)therapy and TME. Severe bladder morbidity was very limited. Mild to moderate urinary frequency and urgency remained elevated during follow-up. Mild to moderate incontinence increased during follow-up. Irritative bladder symptoms (pain, cystitis, dysuria) were reported at EoT but reduced to baseline level during follow-up.

PO-1399 Bowel delineation methods and prediction of acute and late diarrhea in radiotherapy of anal cancer

K.S. Storm 1 , S. Homburg 1 , G.F. Persson 1,2 , C.P. Behrens 1,3 , P. Sibolt 1 , K.G. Spindler 4,5 , C. Kronborg 6,7 , E. Serup-Hansen 1

1 Copenhagen University Hospital - Herlev and Gentofte, Department of Oncology, Copenhagen, Denmark; 2 University of Copenhagen - Faculty of Health Sciences , Department of Clinical Medicine, Copenhagen, Denmark; 3 Technical University of Denmark, Department of Health Technology, Roskilde, Denmark; 4 Aarhus University Hospital, Department of Experimental Clinical Oncology, Aarhus, Denmark; 5 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark; 6 Danish Centre for Particle Therapy, ., Aarhus, Denmark; 7 Aarhus university, Department of Clinical Medicine, Aarhus, Denmark Purpose or Objective Concomitant chemo-radiotherapy is the standard of care for anal cancer. The treatment is associated with significant acute- and late gastro-intestinal (GI) toxicity. Several studies have shown a correlation between GI toxicity and the volume of irradiated bowel. However, bowel delineation is not consistent in different clinical trials and this affects the recommended dose constraints and makes comparison difficult. Constraints are mainly applied for acute toxicity, but patients also experience late GI toxicity impacting their quality of life. Plan-A is a prospective, national Danish trial evaluating toxicity, that included patients with anal cancer treated with VMAT/IMRT-planned chemo-radiotherapy from 2015-2021. The purpose of this study is to evaluate which bowel delineation approach leads to the optimal prediction of acute and late diarrhea in patients with anal cancer receiving concomitant chemo-radiotherapy

Materials and Methods