ESTRO 2024 - Abstract Book

S674

Clinical - Breast

ESTRO 2024

2771

Proffered Paper

EORTC 22922/10925 trial: Outcomes according to systemic therapy

Orit Kaidar-Person 1 , Peggy Giasafaki 2 , Liesbeth Boersma 3 , Peter De Brouwer 4 , Caroline Weltens 5 , Carine Kirkove 6 , Karine Peignaux-Casasnovas 7 , Volker Budach 8 , Femke van der Leij 9 , Ernest Vonk 10 , Nicola Weidner 11 , Sofia Rivera 12 , Geertjan van Tienhoven 13 , Alain Fourquet 14 , Georges Noel 15 , Mariacarla Valli 16 , Matthias Guckenberger 17 , Eveline Koiter 18 , Severine Racadot 19 , Roxolyana Abdah-Bortnyak 20 , Harry Bartelink 21 , Henk Struikmans 22 , Catherine Fortpied 2 , Philip Poortmans 23 1 Sheba Medical Center, Radiation Oncology, Ramat Gan, Israel. 2 EORTC, HQ, Brussels, Belgium. 3 Maastro, Radiation Oncology, Maastricht, Netherlands. 4 Institute Verbeeten, Radiation Oncology, Tilburg, Netherlands. 5 University Hospital Leuven, Radiation Oncology, Leuven, Belgium. 6 University Hospital Saint Luc, Radiation Oncology, Brussels, Belgium. 7 Centre Georges François Leclerc, Radiation Oncology, Dijon, France. 8 Comprehensive Cancer Center, Radiation Oncology, Berlin, Germany. 9 University Medical Centre Utrecht, Radiation Oncology, Utrecht, Netherlands. 10 Institute for Radiation Oncology RISO, Radiation Oncology, Deventer, Netherlands. 11 University Hospital, Radiation Oncology, Tübingen, Germany. 12 Gustave Roussy Cancer Centre, Radiation Oncology, Villejuif, France. 13 Cancer Center Amsterdam, Radiation Oncology, Amsterdam, Netherlands. 14 Institut Curie, Radiation Oncology, Paris, France. 15 Centre Paul Strauss, Radiation Oncology, Strasbourg, France. 16 Sant Anna Hospital, Radiation Oncology, Como, Italy. 17 University Hospital Zurich, Radiation Oncology, Zurich, Switzerland. 18 Medisch Spectrum Twente, Radiation Oncology, Enschede, Netherlands. 19 Centre Léon Bérard, Radiation Oncology, Lyon, France. 20 Rambam Medical Center, Radiation Oncology, Haifa, Israel. 21 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, Netherlands. 22 Leiden University Medical Centre, Radiation Oncology, Leiden, Netherlands. 23 University of Antwerp, Radiation Oncology, Antwerp, Belgium

Purpose/Objective:

The EORTC 22922/10925 trial [1] is a randomized clinical trial that investigated the impact on overall survival (OS) of elective internal mammary and medial supraclavicular (IM-MS) radiation therapy (RT) in breast cancer stage I – III. Surgery for the primary tumour and axillary lymphatics, chest wall RT, boost RT after whole breast RT in breast conserving therapy (BCT), and systemic therapy were per physician’s preference. The aim of the current analysis is to assess breast cancer outcomes according to systemic therapy given.

Material/Methods:

Data with a median follow- up of 15.7 years were extracted from the trial’s case report forms. Cumulative incidence curves of breast cancer events were produced. An exploratory analysis of the effect of the type of adjuvant systemic therapy was conducted using the Fine & Gray model accounting for competing risks and adjusted for baseline patient and disease characteristics and treatment. The significance level was set at 5%, 2-sided. Frequency tables were used to describe breast cancer events.