Neoadjuvant and Adjuvant Ribociclib and ET for Clinically High-risk ER+ and HER2- Breast Cancer

This is an open-label, multicenter international trial in men and women with primary operable HR+/HER2-, ki67≥20%, grade 2 or 3 and stage II breast cancer to evaluate safety and long-term efficacy of a non-chemo treatment in patients biologically responders to neoadjuvant ribociclib and letrozole. This study aims to evaluate whether chemotherapy could be avoided for initial high-risk clinicopathological breast cancer patients that are converted to low genomic risk assessed by Risk of Recurrence-low (ROR-low) at 6 months of letrozole - ribociclib neoadjuvant treatment by continuing with this treatment in adjuvant setting.