ESTRO 2025 - Abstract Book

S563

Clinical - Breast

ESTRO 2025

Conclusion: VMAT-SIB-FFF balances target coverage, dosimetric and radiobiological performance with favorable results for the heart and left lung and acceptable plans for contralateral OARs.

Keywords: simultaneous integrated boost, FFF, breast cancer

3168

Digital Poster 3D Imaging in Breast Cancer: A Novel Scanning Method to Quantify Breast Volume Changes During and After Radiotherapy – A Prospective Clinical Trial Sandra Boyaci 1 , Koban Konstantin 2 , Stephan Schönecker 1 , Stefanie Corradini 1 , Elena Bensmann 3 , Friederike Hagemann 4 , Annemarie Zinn 1 , Mohamed Shouman 1 , Lukas Kaesmann 1 , Claus Belka 1 , Riccardo Giunta 2 , Montserrat Pazos 1 1 Radiotherapy Department, LMU, Munich, Germany. 2 Plastic Surgery Department, LMU, Munich, Germany. 3 Gynecology Department, Red Cross Hospital, Munich, Germany. 4 Gynecology Department, LMU, Munich, Germany Purpose/Objective: The evaluation of cosmetic outcomes after radiation treatment for breast cancer patients is not standardized. Our study aims to quantify changes in breast volume - natural or reconstructed - during and after adjuvant radiotherapy (RT) using a novel 3D surface imaging (3DSI). This information can help clinicians to improve patient counseling on long-term breast changes. Material/Methods: This prospective registry tracks breast cancer patients undergoing RT to the breast/chest wall and axillary lymph nodes (± internal mammary nodes) at a university hospital. The Vectra WB360 Scanner (Canfield®) acquired 3D surface images of the thorax at five time points: first and last day of RT, 3, 12, and 24 months after RT. Breast volumes were calculated using integrated Mirror software (Canfield®) based on anatomical landmarks, as illustrated in Figure 1 . Volume changes were assessed in irradiated and non-irradiated breasts . Correlations with weight, surgery type (BCS or SSM), PTV volume, and radiation technique (3D-CRT vs. VMAT) were evaluated. Statistical analyses were conducted using SigmaPlot 12.0 (Systat Software Inc.) and IBM SPSS Statistics 18 (IBM Corp). At each time point PROMS (EORTC QLQ-C30 and BR23) were collected

Results: 40 consecutive breast cancer patients indicated for adjuvant RT to the breast/chest wall and lymph nodes were recruited (February 2021 – February 2022). A total of 167 scans (3DSIs) were acquired. Patient Characteristics: