ESTRO 2023 - Abstract Book

S1014

Digital Posters

ESTRO 2023

1 AOU Careggi - University of Florence, Radiotherapy Unit, Florence, Italy; 2 AOU Careggi - University of Florence, Diagnostic Cardiology, Cardiothoracic, and Vascular Department, Florence, Italy; 3 Istituto Fiorentino di Cura e Assistenza (IFCA), CyberKnife Center, Florence, Italy; 4 AOU Careggi - University of Florence, Medical Physics Unit, Oncology Department, Florence, Italy Purpose or Objective This study aims to assess heart toxic effect using a reliable cardiac assessment with standard and 3-dimensional (3D) echocardiography and left ventricular (LV) global longitudinal strain (GLS) in patients receiving a 5-fraction (total dose 26Gy) postoperative radiation therapy (RT) for breast cancer (BC). Materials and Methods SAFE-FORWARD is an observational prospective cohort study (NCT04842409). Patient population included both invasive and ductal carcinoma in situ (DCIS) BC receiving ultra-hypofractionated whole breast irradiation (WBI) after breast conserving surgery (BCS). All enrolled patients are prospectively monitored for 12 months, receiving a complex cardiological assessment before RT start (baseline), and at 2-, 6-, and 12-month after RT end of treatment. Both acute and early-late toxicity are scored according to EORTC/RTOG and CTCAE (v.5) scales. The primary endpoint is defined as detection of any subclinical impairment in myocardial function and deformation (decrease ≥ 10%) measured with standard and 3D echocardiography and LV GLS. Results Overall, 40 women (median age 66 years; range, 48-84) were enrolled in the study. We analysed patients who had completed the cardiological assessment at 12 months. Baseline demographic, tumour, and cardiovascular profiles are summarised in Table 1. All patients received ultra-hypofractionated WBI (26 Gy in 5 fractions), 25 patients also received adjuvant endocrine therapy.

GLS worsened 4% or less, both for the left- and right-side treated breast, and remained in normal range for all the time points. The only exception was for RVGLS at 6 months for right-sided treatment where it reached a borderline value (- 17.4±4.9 SE). 3D-LVEF remains stable during observation, both for the left- and right-side treated breast (Figure 1).