Local management of second ipsilateral breast cancer events after primary breast-conserving therapy: an international Delphi consensus

Hannoun-Levi JM, Margenthaler JA, Anderson B, Di Micco R, Arthur DW, Aznar M, Burke EE, de Boniface J, Dietz JR, Dodwell D, Fredriksson I, Gentilini OD, Guix B, Gutierrez C, Kothari A, Lyons JA, Meattini I, Montero-Luis A, Mourtada F, Nguyen TT, Polgar C, Poortmans P, Rocco N, Sackey H, Sarantou T, Showalter SL, Strnad V, Kuehn T, Volders J, Vrancken-Peeters MJ, Yashar C, Rubio IT, Gahm J, Zeidan Y, Kaidar-Person O, Dirbas FM (2026)

Publication Type: Journal article, Review article

Publication year: 2026

Journal

Book Volume: 27

Pages Range: e407-e419

Journal Issue: 9

DOI: 10.1016/S1470-2045(26)00177-4

Abstract

Management of second ipsilateral breast cancer events (iBCEs) remains controversial, and there is a need to collate existing evidence and international guidance on patient selection and local treatment strategies. This project, endorsed by US and European surgical and radiation oncology societies, aimed to gather expert consensus on these issues. A questionnaire on second iBCE local treatment was developed and reviewed by a core group of eight experts, and Delphi methodology was applied over two rounds to 36 panellists, including radiation oncologists, breast surgeons, a plastic surgeon, and medical physicists. Consensus was predefined as agreement of 75% or higher. After two rounds, consensus was reached for 78 (80%) of 97 items. Panellists agreed that patient preferences are central to decision making (100%) and that a second breast-conserving therapy represents a reasonable option for selected patients (100%). Criteria associated with greater suitability for second breast-conserving therapy included an interval between surgeries of at least 60 months, low-risk accelerated partial breast irradiation classification, luminal molecular profile, and no grade 3 late toxicity related to the first breast-conserving therapy. HER2 (also known as ERBB2 )-positive or triple negative subtypes were not viewed as absolute contraindications. Strong consensus was also observed regarding the importance of tumour-to-breast volume ratio, clear surgical margins, and tumour bed reirradiation. For patients undergoing mastectomy, immediate autologous reconstruction was preferred (94%) over implant-based approaches (75%). This international Delphi consensus offers structured guidance for the local management of second iBCE and supports shared decision making and individualised treatment planning.

Authors with CRIS profile

Involved external institutions

University Hospitals of Cleveland / Case Western Reserve University Hospital United States (USA) (US) Università degli Studi di Firenze / University of Florence Italy (IT) HM Hospitals Spain (ES) Thomas Jefferson University Hospitals United States (USA) (US) Westchester Medical Center University Hospital (WMC) United States (USA) (US) Levine Cancer Institute United States (USA) (US) University of Virginia (UVA) United States (USA) (US) Universität Ulm Germany (DE) Diakonessenhuis Utrecht Netherlands (NL) Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital (NKI / NKI-AVL) Netherlands (NL) University of California, San Diego (UC San Diego, UCSD) United States (USA) (US) Clínica Universidad de Navarra Spain (ES) Karolinska Institute Sweden (SE) Baptist Health South Florida United States (USA) (US) Chaim Sheba Medical Center at Tel HaShomer / המרכז הרפואי עש חיים שיבא – תל השומר‎‎ Israel (IL) Stanford University United States (USA) (US) University of Wisconsin - Madison United States (USA) (US) Országos Onkológiai Intézet / National Institute of Oncology Hungary (HU) University of Antwerp / Universiteit Antwerpen Belgium (BE) University of Côte d'Azur / Université Côte d'Azur France (FR) Washington University in St. Louis United States (USA) (US) Ospedale San Raffaele (früher: Centro San Raffaele del Monte Tabor Foundation) Italy (IT) Virginia Commonwealth University (VCU) United States (USA) (US) University of Kentucky United States (USA) (US) Capio S:t Görans sjukhus Sweden (SE) New York University (NYU) United States (USA) (US) University of Oxford United Kingdom (GB) Hospital Clínic de Barcelona Spain (ES) Catalan Institute of Oncology / Institut Català d'Oncologia (ICO) Spain (ES) Guy's and St Thomas' (NHS Foundation Trust) United Kingdom (GB)

How to cite

APA:

Hannoun-Levi, J.M., Margenthaler, J.A., Anderson, B., Di Micco, R., Arthur, D.W., Aznar, M.,... Dirbas, F.M. (2026). Local management of second ipsilateral breast cancer events after primary breast-conserving therapy: an international Delphi consensus. Lancet Oncology, 27(9), e407-e419. https://doi.org/10.1016/S1470-2045(26)00177-4

MLA:

Hannoun-Levi, Jean Michel, et al. "Local management of second ipsilateral breast cancer events after primary breast-conserving therapy: an international Delphi consensus." Lancet Oncology 27.9 (2026): e407-e419.

BibTeX: Download