ESTRO 2024 - Abstract Book

S591

Clinical - Breast

ESTRO 2024

Rebecca Moser 1 , Sophie Therese Behzadi 1 , Nina Mayr 2 , Sophia Kiesl 1 , Jana Nano 1 , Stephanie Elisabeth Combs 1,3,4 , Kai Joachim Borm 1 1 TUM School of Medicine and Health, Department of Radiation Oncology, Munich, Germany. 2 Michigan State University, School of Human Medicine, East Lansing, MI, USA. 3 Institute of Radiation Medicine, Helmholtz Zentrum Munich, Munich, Germany. 4 German Consortium for Translational Cancer Research (dktk), Partner Site Munich, Munich, Germany

Purpose/Objective:

The risk of ischemic coronary events increases by 7.4% for every Gray (mean cardiac dose) in radiotherapy for left sided breast carcinoma(1). The cardiac dose can be reduced by using deep inspiration breath-hold (DIBH) during daily radiation treatment(2). However, the success of DIBH depends on the patient's own physical capacity for breath holding and the patient’s ability for active daily cooperation(3,4). Currently, patients are given variable verbal explanations and instructions at the time of treatment planning but no formal respiratory training to prepare them for DIBH, and actual DIBH performance during daily treatment is often inconsistent in individual patients. The B REST study aims to improve patient compliance and performance of DIBH to further reduce the cardiac dose from left breast radiation,and to improve cooperation and patient satisfaction through an active and formal pre treatment respiratory training program combined with relaxation training (R&R). The randomized design of the study will test these interventions compared to current conventional DIBH instruction.

Material/Methods:

The B-REST study has been approved by the ethics committee of the Technical University of Munich and is funded by the German Cancer Aid. B-REST is registered at trials.gov (NCT05975190). The study is designed to assess the impact of R&R on patients with left-sided breast carcinoma undergoing radiotherapy. The patients will be randomly assigned to either an experimental arm, which will receive the R&R, versus a standard arm that will not receive the R&R. The training program in the experimental arm includes breath hold training, music, and nature sounds that patients can listen to on an MP3 player. The training is offered one week before the planning CT scan and patients are encouraged to practice independently.

Both groups complete standardized questionnaires about their well-being and satisfaction at prospective time points before, during the radiation treatment course, as well as at 6 weeks follow-up. The study team will collect case report forms (e.g. compliance and toxicity data), conduct examinations, and evaluate physical data from the radiation treatment plans, including comparative cardiac dose metrics in the dosimetry plans of DIBH versus free breathing (as a measure of the gains in heart dose sparing).

Results:

Between June 2022 and October 2023, 47 patients have been recruited to the B-REST study, 24 patients in the experimental arm, 23 patients in the standard arm. A total enrollment of 108 patients is planned. We present the rationale, study concept and design of the B-REST Trial. Initial experience from the currently enrolled study cohort and preliminary results will be discussed. Overall, the study enjoys great acceptance among the patients. The