In this video, I discuss ribociclib and abemaciclib in early stage HR /HER2- breast cancer. Both are CDK 4/6 inhibitors which interfere with the cell cycle and are used in combination with endocrine therapy to decrease the risk of recurrence. Ribociclib: 400 mg daily 21 days on/7 days off for 3 years At 5 years: absolute improvement in invasive disease free survival (survival without disease) was 4.5% in patients receiving ribociclib (81% in endocrine therapy alone versus 85.5% in ribociclib end