Organ Culture for Endocrine Resistant Next Line: A Treatment Selection Study in Metastatic Breast Cancer

This study evaluates whether testing fresh tumor samples outside the body can help guide treatment selection for patients with hormone receptor-positive, HER2-negative metastatic breast cancer that has progressed during endocrine therapy. A biopsy sample from each participant will be tested using an ex vivo organ culture (EVOC) platform, which preserves the tumor tissue and allows researchers to assess its response to different anticancer treatments. The results will be used to help select the participant\'s next systemic treatment. The main objective is to evaluate the proportion of patients whose cancer responds to treatment selected using this approach. The study will also assess how long the cancer remains controlled, overall survival, and the relationship between laboratory test results and clinical outcomes.