Pragmatic Study to Optimize Neoadjuvant Treatment and Surgical De-escalation in HR+/HER2- Early Breast Cancer Using Oncotype DX and Abemaciclib

Women aged 18 years or older with histologically confirmed operable or inoperable ER-positive (\>10%)/HER2-negative invasive breast carcinoma (stage II-IIIB), candidate to receive neoadjuvant chemotherapy according to the shared decision of a multidisciplinary tumor board, and who are not eligible to receive upfront breast conservative surgery AND/OR are candidate to lymph node. All eligible patients will undergo ODX RS tumor assessment in the baseline biopsy. They will receive NET plus abemaciclib or NCT for 6 months as per MDT decision, according to tumor stage, tumor histology, patient menopausal status and ODX RS results. At the end of the neoadjuvant treatment, all patients will be discussed again in a multidisciplinary tumor board and a new surgical indication will be given according to the post-treatment clinical and radiological assessment.After surgery, patients who received NET+abemaciclib may receive adjuvant chemotherapy according to the multidisciplinary tumor board indication.dissection.