ESTRO 2025 - Abstract Book

S557

Clinical - Breast

ESTRO 2025

3029

Digital Poster Deep inspiration breath-hold (DIBH) in breast radiotherapy: cardiac sparing and clinical implications Anna Bertolini 1,2 , Ruggero Spoto 1 , Antonio Marco Marzo 1 , Luca Dominici 1 , Sara Stefanini 1,2 , Veronica Vernier 1,2 , Beatrice Marini 1,2 , Francesca Lobefalo 1 , Stefano Tomatis 1 , Davide Franceschini 1 , Marta Scorsetti 1,2 1 Radiotherapy, IRCCS Humanitas Research Hospital, Rozzano, Italy. 2 Biomedical Sciences, Humanitas UniversityHumanitas University, Pieve Emanuele, Italy Purpose/Objective: Breast cancer patients often have long survival rates, making the minimization of radiotherapy side effects a critical goal. For left-sided breast cancer, cardiac radiation exposure is closely linked to both acute and late toxicity. The advent of volumetric modulated arc therapy (VMAT) has improved high-dose conformity to the tumor but has increased low-dose exposure to organs at risk. Deep inspiration breath-hold (DIBH) is a radiotherapy technique specifically designed to mitigate cardiac radiation exposure. By holding a deep breath, patients displace the heart away from the chest wall, reducing radiation doses to cardiac tissues. Combining VMAT with DIBH could be a promising approach to minimize cardiac toxicity. This retrospective study assesses the dosimetric impact of DIBH combined with VMAT on the heart and left anterior descending coronary artery (LADCA) in left-sided breast cancer patients and evaluates its clinical implications. Material/Methods: We analyzed left-sided breast cancer patients who underwent adjuvant VMAT radiotherapy between January 1, 2017, and December 31, 2023. Treatment planning employed the Varian™ video-based real-time position management (RPM) system for DIBH. Patients with significant pulmonary comorbidities or unable to perform DIBH were excluded. A prescribed dose of 40.5 Gy in 15 fractions was delivered to the breast or thoracic wall and axillary lymph nodes, with a boost of 48 Gy to the surgical bed. Results: Fifty-seven female patients were included, with a median age of 46.9 years (SD ± 6.6). Most patients (56, 98.3%) underwent quadrantectomy, and one (1.8%) had a mastectomy. All patients completed radiotherapy; 48 (84.2%) received a boost, and 2 underwent axillary lymph node irradiation. Dosimetric data for cardiac structures are detailed in Table 1. The median follow-up was 38 months, with 54 (94.7%) patients successfully monitored. Among them, 44 (87%) remained in remission with no major health issues, 1 patient experienced cancer recurrence, 1 had a non-cancer-related death, and 1 suffered a cardiac event involving mild mitral and tricuspid valve insufficiency. Hormonal therapy-related complications included endometrial polyps, uterine myomas and osteopenia in 7 patients.

Conclusion: VMAT combined with DIBH effectively reduces cardiac radiation exposure in left-sided breast cancer radiotherapy, achieving favorable clinical outcomes with minimal cardiac toxicity. Prospective multicenter studies with extended follow-up are warranted to confirm long-term benefits and further improve patient outcomes.

Keywords: Deep inspiration breath hold,VMAT,cardiac sparing