ESTRO38 Congress Report

Radiobiology

2. Analysis of biomarkers for late radiotherapy toxicity in the REQUITE project. (E38-1219) Christopher Talbot

Department of Genetics and Genome Biology, University of Leicester, Leicester, UK

Context of the study Radiotherapy is a very effective method of killing tumours, but causes side effects in some patients. The side effect range frommild skin burns which quickly heal, through long- term symptoms that affect quality-of-life (e.g. hard lumps in the breast or rectal bleeding in prostate cancer patients), to organ damage and secondary cancers. Predicting which patients will suffer these side effects is the primary aim of the REQUITE project. Overview of abstract The aim of the research was to recruit large cohorts of patients treated with radiotherapy for breast, lung and prostate cancer in multiple hospitals across Europe. Extensive information is collected on each patient including medical history, treatment factors and radiotherapy imaging data. Blood samples were collected to allow for genetic and transcriptomic testing, with a sub-cohort also tested for the leading biomarker for radiotherapy prediction (the Radiation-Induced Lymphocyte Apoptosis or RILA assay). All the data is stored in a central database and the samples in a central biobank. What were the three main findings of your research? 1. Genome-wide association studies were carried out to identify genetic variants that predict side effect 2. A final evaluation was carried out to determine how effective the RILA assay is at adding predictive value 3. Breast cancers patients treated in the morning tended to have worse side effects than those treated in the afternoon. This effect was found to be strongest in patients with particular forms of two genes associated with circadian rhythm: Nocturnin and PER3

What impact could your research have? Our research is helping to improve predictive models for radiotherapy side effects. When the models provide high enough predictive value they can be used in stratified clinical trials in which treatment will be change according to the calculated risk of side effects. Is this research indicative of a bigger trend in oncology? This research is part of the trend towards personalised medicine, in which the treatment pathway is guided by the individual’s genetic and environmental make-up.

RADIOBIOLOGY | Congress report

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