Abstract P4-11-12: CLEAR-B - Adjuvant therapy effectiveness in patients with primary breast cancer: A retrospective registry study

Abstract Objectives: Adjuvant endocrine treatment for premenopausal patients with early hormone receptor positive HER2 negative (HRpos/HER2neg) breast cancer (BC) is supposed to depend on the estimated risk profile. Patients with a high recurrence risk should be offered aromatase inihibtors (AI) and ovarian function suppression (OFS) and patients with a low recurrence risk tamoxifen (TAM) with or without OFS. However utilization of these treatment options is diverse even in high risk patients. Aim of this retrospective study was therefore to assess the treatment patterns and outcomes of endocrine treatment variability in a real world setting. Methods: CLEAR-B is an anonymized retrospective study that uses prospectively collected data generated in the course of the certification process of breast centers in the period from January 2016 to June 1019 and from January 2022 to December 2023. Eligible were premenopausal patients with early HRpos/HER2neg BC an intermediate high and very high recurrence risk. Patient and disease characteristics are documented along with information about recommended and performed adjvuant treatments as well as information about recurrence and death. Results: The first patient was documented in February 2023. A total of 3.000 patients will be documented until August 2024 at 75 study sites in Germany. An interim analysis showed that the majority of documented patients is treated with tamoxifen despite an increased recurrence risk. Changes in therapy patterns and patient/disease characteristics will be analyzed according to patient risk profiles and in the two assessment periods (2016-2019 vs. 2022-2023). Additionally the context of healthcare provision (treatment centers vs. de-central healthcare) will be investigated. Summary: Awareness of treatment standards along with efficacy data and quality of life data is important to make informed therapy decisions about adjuvant endocrine treatment together with the patients. A full analysis of treatment patterns over time and outcomes will be presented at the conference. Citation Format: Bahriye Aktas, Hanna Huebner, Andreas Hartkopf, Maggie Banys-Paluchowski, Ingolf Juhasz-Böss, Nadia Harbeck, Hans-Christian Kolberg, Elmar Stickeler, Marcus Schmidt, Marc Thill, Michael Untch, Thorsten Kühn, Nina Ditsch, Lothar Häberle, Manuel Hoerner, Daniel Anetsberger, Kathrin Nicole Truch, Christian Roos, Christian Mann, Erik Belleville, Tanja Fehm, Peter A. Fasching. CLEAR-B - Adjuvant therapy effectiveness in patients with primary breast cancer: A retrospective registry study [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-11-12.