The BRAVE-HEART trial is an ambispective, observational, non-randomized study conducted at Fondazione IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico) Policlinico San Matteo (Pavia, Italy). It aims to document and quantify the cardiac dose reduction achievable with breast radiotherapy performed in Deep Inspiration Breath Hold (DIBH) using the Active Breathing Coordinator (ABC) system. Dosimetric parameters from DIBH treatments are evaluated, with free-breathing treatment plans and data from patients treated under free-breathing conditions used as reference. Secondary analyses include treatment reproducibility, comparison of radiotherapy techniques and fractionation schedules, impact of the simultaneous integrated boost (SIB), and assessment of acute and late toxicity during follow-up.

The BRAVE-HEART study is an ambispective, observational, non-randomized, single-center study conducted at Fondazione IRCCS Policlinico San Matteo (Pavia, Italy). The purpose of the study is to document and quantify the heart-sparing effect of breast radiotherapy delivered with Deep Inspiration Breath Hold (DIBH) assisted by the Active Breathing Coordinator (ABC), as implemented in routine clinical practice.

The study includes patients with stage I-III breast carcinoma undergoing radiotherapy according to institutional standards, most commonly after conservative or radical surgery. Radiotherapy is delivered using three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated/volumetric modulated arc therapy (IMRT/VMAT) techniques, with conventional, hypofractionated, or ultrahypofractionated regimens, with or without a simultaneous integrated boost (SIB) to the tumor bed.

Eligibility for ABC-assisted DIBH is assessed at CT simulation. Patients unable to perform or maintain the breath-hold maneuver are treated under free-breathing conditions. Free-breathing treatment plans and data from patients treated under free-breathing conditions are used as dosimetric references to quantify the magnitude of cardiac dose reduction achievable with ABC-assisted DIBH.

The primary objective is to assess the reduction in radiation dose delivered to the heart and its substructures, particularly the left anterior descending coronary artery (LAD), when radiotherapy is performed with ABC-assisted DIBH. Secondary objectives include evaluating treatment reproducibility and the feasibility of ABC-DIBH in daily practice, comparing dosimetric parameters among different radiotherapy techniques (3D-CRT vs VMAT/IMRT), describing the impact of different fractionation schemes (conventional, hypofractionated, and ultrahypofractionated) and SIB on organs-at-risk exposure, and collecting data on acute and late toxicity during follow-up.

The study aims to provide real-world evidence on the effectiveness, reproducibility, and clinical applicability of ABC-assisted DIBH for cardiac sparing in breast cancer radiotherapy.

Inclusion Criteria:

• Diagnosis of stage I-III breast carcinoma with an indication for radiotherapy
• Invasive carcinoma or ductal carcinoma in situ (DCIS)
• Radiotherapy delivered using three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated/volumetric modulated arc therapy (IMRT/VMAT) techniques
• Ability to actively cooperate in using the Active Breathing Coordinator (ABC) system for Deep Inspiration Breath Hold (DIBH), or treated under free-breathing conditions when DIBH is not feasible
• Age ≥18 years
• Ability to provide written informed consent for the anonymous use of data for research purposes

Exclusion Criteria:

• Severe health problems or profound hearing loss
• Severe respiratory or cardiovascular conditions in the medical history that contraindicate radiotherapy
• Inability to provide written informed consent for the anonymous use of data for research purposes
• Absolute contraindications to radiotherapy (e.g., pregnancy, or inability to maintain the correct treatment position)

Ambispective cohort of patients with stage I-III breast carcinoma treated with radiotherapy at Fondazione IRCCS Policlinico San Matteo. Radiotherapy may include whole or partial breast or chest wall, with or without nodal irradiation, delivered with 3D-CRT or IMRT/VMAT. The Active Breathing Coordinator (ABC) system is used for DIBH when feasible; patients unable to perform DIBH are treated under free-breathing conditions. Different fractionation schedules and SIB may be used according to clinical indications.