Oncotype DX Breast Cancer Assay

This phase III trial compares standard of care hormone therapy plus ribociclib to chemotherapy followed by hormone therapy plus ribociclib for the treatment of patients with high anatomic stage breast cancer with low risk of the cancer returning (low risk recurrence). Ribociclib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Hormone therapy, with letrozole, anastrozole or exemestane, lowers the amount of estrogen made by the body. This may help stop the growth of tumor cells that need estrogen to grow. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Hormone therapy plus ribociclib may work as well as chemotherapy followed by hormone therapy plus ribociclib for the treatment of high anatomic stage breast cancer with low recurrence risk.