ESTRO 2020 Abstract Book

S35 ESTRO 2020

OC-0076 Insights into the evidence-based practice of hypofractionated radiotherapy in Europe B. Tawk 1,4 , D. Rodin 2 , G. Axelsson 3 , Y. Lievens 4 1 Universitätsklinikum Heidelberg, Radiation oncology, Heidelberg, Germany ; 2 Radiation Medicine Program- Princess Margaret Cancer Centre, University of Toronto- Radiation Oncology, Toronto, Canada ; 3 European Society for Radiotherapy and Oncology, Public Affairs, Brussels, Belgium ; 4 Ghent University Hospital and Ghent University, Radiation Oncology, Brussels, Belgium ; 4 Bouchra Tawk, German Cancer Consortium (DKTK) core site Heidelberg, Germany Purpose or Objective Effıcacy of hypofractionationed radiotherapy has been demonstrated in clinical trials. We previously reported on global practice patterns of hypofractionation in a worldwide survey distributed through the ESTRO Global Impact of Radiotherapy in Oncology (GIRO) initiative. This subgroup analysis aims to evaluate practice background of radiotherapists, uptake of hypofractionation, its facilitators and barriers in curative breast and prostate cancer, and for bone metastases across Europe. Material and Methods Between January and December 2018, 2,259 radiation oncologists responded to an international anonymous electronic survey distributed in English, Spanish, Japanese and Mandarin. Demographic and professional characteristics were collected. Preference for hypofractionation was evaluated across breast, prostate, cervix and bone metastases in curative and palliative clinical scenarios. Respondents reported preferred fractionation regimens for each scenario (dose per fraction(fx), total number of fx), and perceived barriers and facilitators. Results There were 1,259 European respondents (57%) from 46 countries, the majority practicing in the European Union- 28 (86%). Highest response rates came from Italy (12%), the United Kingdom (11%), Spain (10%), Germany (8%) and Denmark (5%). In breast cancer, post-lumpectomy, hypofractionation uptake was 89% in node negative and 48% in node positive disease; post-mastectomy, rates were 50% and 35% respectively (p<0.0001). In prostate cancer, uptake was in 67% in low risk, 63% intermediate, 49% high-risk and 28% of cases requiring pelvic irradiation (p<0.00001). For palliation of bone metastases, 96% favored hypofractionation. In case of hypofractionation for breast cancer, 64% prescribed 2.5-3Gy in 15-16 fx irrespective of indication. Higher fraction numbers were noted in prostate varying by indication (22% 3-3.5Gy/20 fx in low-intermediate risk & 18% 2.5-3Gy/28 fx in high-risk or pelvic irradiation disease). Single fraction (8-9Gy) was favored in uncomplicated bone metastasis (38%) whereas 5 fx of 4- 5Gy was favored in cases complicated by fracture (21%), cord compression (21%) or soft tissue component (25%). Evidence (95%), equivalent local control (93%) and equivalent toxicity (79%) were consistently the main facilitators in curative setting. Higher barriers to hypofractionation were observed in prostate compared to breast cancer, chiefly late toxicity (54% vs. 38%, p<0.0001), lack of long-term data (39% vs. 33%, p<0.058) and acute toxicity (37% vs. 21%, p<0.00001).

Conclusion In Europe, acceptance of hypofractionated radiotherapy is high in node-negative breast-conserving cases and moderate in low-intermediate risk prostate cancer. Though hypofractionation is the standard for bone metastases, sıngle fraction uptake remains low. Barriers to optimal utilization of hypofractionation need addressing through continuing education and guideline promotion to improve translation of evidence into practice OC-0077 Factors Associated with the Global Availability of Radiotherapy Services: an IAEA analysis J.A. Polo Rubio 1 , E. Zubizarreta 1 , Y. Lievens 2 , M. Barton 3 , D. Rodin 4 , V.D. Jake 5 , S. Grover 6 , M. Abdel-Wahab 1 1 International Atomic Energy Agency, Division of Human Health, Vienna, Austria ; 2 University of Gent, Radiation Oncology, Gent, Belgium ; 3 University of South Wales, Radiation Oncology, Sidney, Australia ; 4 Princess Margaret Cancer Centre. University of Toronto, Radiation Oncology, Toronto, Canada ; 5 The University of Western Ontario, Oncology, London, Canada ; 6 Hospital of the University of Pennsylvania, Radiation Oncology, Philadelphia, USA Purpose or Objective To assess factors associated with the global availability of radiotherapy services. The intent of understanding these factors is to provide insight into the various macro- determinants associated with successful and sustainable radiotherapy over time and to provide guidance on the sustainability of current and future investments in radiation therapy.