ESTRO 2025 - Abstract Book

S627

Clinical - Breast

ESTRO 2025

Conclusion: Concurrent TDM1 and locoregional RT in HER2-positive breast cancer with residual disease is feasible but associated with a high risk of RIP (19.35%), particularly in patients with pre-existing pulmonary conditions. Careful patient selection and close monitoring are essential. Prospective studies are warranted to refine dosimetric guidelines and improve safety.

Keywords: Breast Cancer, TDM1, Radiation-Induced Pneumonitis

References: Salvestrini V, Kim K, Caini S, Alkner S, Ekholm M, Skyttä T, Becherini C, Coles CE, Kaidar-Person O, Offersen B, de Azambuja E, Visani L, Cortes J, Harbeck N, Rugo HS, Isacke CM, Marangoni E, Morandi A, Lambertini M, Poortmans P, Livi L, Meattini I. Safety profile of trastuzumab-emtansine (T-DM1) with concurrent radiation therapy: A systematic review and meta-analysis. Radiother Oncol. 2023 Sep;186:109805. doi: 10.1016/j.radonc.2023.109805. Epub 2023 Jul 10. PMID: 37437610.

4462

Mini-Oral Fibrosis and unfavorable cosmesis after breast conserving therapy are negatively associated with various quality of life domains (ID: NCT05263362) Marije C.A.W. Notenboom 1,2 , Taco M.A.L. Klem 3 , Caroline M.E. Contant 4 , Suzanne P. Ribbe 1 , Martine Franckena 1 , Linetta B. Koppert 5 , Marc A.M. Mureau 6 , Erik D. van Werkhoven 7 , Remi A. Nout 1 , Marian B.E. Menke-Pluijmers 2 , Femke E. Froklage 1 1 Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Centre Rotterdam, Rotterdam, Netherlands. 2 Department of Surgery, Albert Schweitzer Hospital, Dordrecht, Netherlands. 3 Department of Surgery, Franciscus Gasthuis & Vlietland, Rotterdam, Netherlands. 4 Department of Surgery, Breast Center South Holland South Maasstad Hospital, Rotterdam, Netherlands. 5 Department of Surgery, Erasmus MC Cancer Institute, University Medical Centre Rotterdam, Rotterdam, Netherlands. 6 Department of Plastic and Reconstructive Surgery, Erasmus MC Cancer Institute, University Medical Centre Rotterdam, Rotterdam, Netherlands. 7 Department of Hematology, Erasmus MC Cancer Institute, University Medical Centre Rotterdam, Rotterdam, Netherlands Purpose/Objective: The majority of breast cancer patients (60-70%) can be treated with breast conserving therapy (BCT) instead of mastectomy. [1] Breast fibrosis is a well-known late side effect of BCT, occurring in 10-30% of patients, with severe fibrosis in 2-5%. [2] Fibrosis can lead to breast retraction, asymmetry and pain, negatively affecting cosmesis and quality of life (QoL). [3] Oncoplastic surgery and improved radiotherapy techniques have been developed, but limited data is available on fibrosis, cosmetic outcomes, and patient-reported QoL in large cohorts with longer follow up. The aim of this study was to investigate how fibrosis and cosmetic outcome both relate to various QoL domains. Material/Methods: The STARLINGS study (ClinicalTrials.gov ID: NCT05263362) is a multicenter cross-sectional observational cohort study involving four Dutch hospitals. Inclusion criteria were: female, aged 18 years or older, treated with BCT for histologically proven invasive breast cancer (pT1-3N0-2aM0) or DCIS. Surgery was performed between 2016 and 2021 followed by adjuvant radiotherapy. Patients had one study visit for physical examination and breast photos. Photos were analyzed with BCCT.core software and patients completed questionnaires: BREAST-Q for BCT, EORTC QLQ-BR23, and EORTC QLQ-C30. A Minimal Clinically Important Difference (MCID) of five points (Δ ≥ 5) was considered clinically relevant.