ESTRO 2022 - Abstract Book

S823

Abstract book

ESTRO 2022

Conclusion Since introduction of CT-based treatment planning around 2005-8, DBCG guidelines for both contouring and dose constraints have been agreed upon, and they are continuously evaluated and modified at national meetings and workshops. As a result most volumes were contoured consistently among centers, but surprisingly, systematic differences were present in some volumes. This illustrates the need for further actions in harmonizing delineation practices for these volumes. Future studies investigating outcomes related to dose to volumes such as the CTVn_IMN, heart and humeral head should consider the variation in delineation practices.

OC-0932 Preoperative radiation therapy in early breast cancer: phase II ROCK trial (NCT03520894)

L. Visani 1 , I. Meattini 1 , G. Francolini 1 , V. Di Cataldo 1 , C. Becherini 1 , J. Nori 2 , M. Bernini 3 , L. Orzalesi 3 , L. Sanchez 3 , E. Scoccimarro 1 , S. Lucidi 1 , C. Bellini 1 , I. Desideri 1 , V. Scotti 1 , R. Doro 4 , L. Masi 4 , M. Loi 1 , S. Bianchi 5 , M. Mangoni 1 , L. Livi 1 1 University of Florence, Department of Experimental and Clinical Biomedical Sciences, Florence, Italy; 2 Azienda Ospedaliero-Universitaria Careggi, Diagnostic Senology Unit, Florence, Italy; 3 Azienda Ospedaliero-Universitaria Careggi, Breast Surgery Unit, Florence, Italy; 4 Istituto Fiorentino di Cura e Assistenza, Department of Medical Physics, Florence, Italy; 5 Azienda Ospedaliero-Universitaria Careggi, Pathology Unit, Florence, Italy Purpose or Objective Breast-conserving surgery (BCS) followed by postoperative radiation therapy (RT) to the residual breast represents the current standard of care for most women affected by early breast cancer (BC). However, standard postoperative regimens are characterized by postsurgical waiting time, socioeconomic consequences and potential acute and late locoregional