ESTRO 2025 - Abstract Book

S170

Brachytherapy -Breast

ESTRO 2025

3026

Proffered Paper Patient selection for APBI: Updated recommendations of the GEC-ESTRO Breast Cancer Working Group based on clinical evidence (2024) Csaba Polgar 1 , Cristina Gutierrez Miguelez 2 , Olivera Ivanov 3 , Viktor Smanyko 1 , Magdalena Stankiewicz 4 , Irene Martinez 5 , Kristina Lössl 6 , Jose Luis Guinot 7 , Jean-Michel Hannoun-Levi 8 , Vratislav Strnad 9 1 Center of Radiotherapy, National Institute of Oncology, Budapest, Hungary. 2 Department of Radiation Oncology, Institut Catalá d’ Oncologia, Barcelona, Spain. 3 Department of Radiation Oncology, Oncology Institute of Vojvodina, Sr Kamenica, Serbia. 4 Brachytherapy Department, Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice Branch, Gliwice, Poland. 5 Department of Radiation Oncology, Hospital Universitario de Navarra, Navarra, Spain. 6 Department of Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland. 7 Department of Radiation Oncology, Fundacion Instituto Valenciano de Oncologia, Valencia, Spain. 8 Department of Radiation Oncology, Centre Antoine-Lacassagne, Nice, France. 9 Department of Radiation Oncology, University Hospital Erlangen, Erlangen, Germany Purpose/Objective: To update recommendations on patient selection criteria for the use of accelerated partial breast irradiation (APBI) based on available clinical evidence. Material/Methods: Between 2010 and 2024, 607 articles were identified by a systematic search of the PubMed, Medline, Scopus and Cochrane database using the keywords "accelerated partial breast irradiation" and "APBI". This search was complemented by searches of reference lists of articles and handsearching of relevant conference abstracts and book chapters. Of these, 11 prospective randomized clinical trials with a minimum median follow-up time of 5 years were identified. The authors reviewed the published clinical evidence on APBI, analyzed the inclusion criteria used, complemented by relevant clinical and pathological studies of standard breast-conserving therapy. The recommendations presented in this summary were developed based on these reviews and analyses in a series of face-to-face meetings. Results: Based on current published clinical evidences, the GEC-ESTRO Breast Cancer Working Group recommends two categories guiding patient selection for APBI: (1) good candidates for APBI including patients ageing at least 40 years with unicentric, unifocal, pTis,T1-2 (≤30 mm) pN0 or pN1mi, all histology types of invasive breast cancer without the presence of an extensive intraductal component (EIC), without extensive lympho-vascular invasion (LVI) and with negative surgical margins (by NSABP criteria), (2) high-risk group, for whom APBI is considered contraindicated; including patients with BRCA 1-2 mutations or ageing ≤40 years; having positive margins, multicentric or large (>30 mm), triple negative tumours, EIC positive, macrometastatic positive lymph nodes (≥pN1a) or unknown axillary status (pNx). Conclusion: Based on emerging clinical evidence, the current valid patient selection criteria could be significantly extended, allowing more patients to be treated with APBI as a part of daily clinical practice in the future.

Keywords: partial breast irradiation, patient selection