# Exploring the Potential of Adjuvant CDK4/6 Inhibitors in Hormone Receptor-Positive Early Breast Cancer: A Consistent Approach for All

## TL;DR

This paper reviews the use of CDK4/6 inhibitors in treating early hormone receptor-positive breast cancer, comparing two key trials and discussing their implications for treatment decisions.

## Contribution

The paper systematically compares the NATALEE and monarchE trials to clarify the role of CDK4/6 inhibitors in high-risk breast cancer patients.

## Key findings

- Ribociclib shows broader applicability and influences decisions on axillary lymph node surgery in high-risk patients.
- Both ribociclib and abemaciclib demonstrate comparable efficacy and manageable safety in adjuvant therapy.
- Unanswered questions remain about optimizing CDK4/6 inhibitor use in early breast cancer treatment.

## Abstract

Cyclin D kinase 4/6 inhibitor has changed the pattern of adjuvant endocrine therapy for early breast cancer. While the results of the NATALEE and monarchE studies are not completely consistent. It is necessary to sort out the differences in these two clinical studies and help to address these unsolved clinical questions

Background/Objectives: Hormone receptor-positive, HER2-negative breast cancer is the most common subtype, with endocrine therapy as the standard treatment. Despite the advancements in adjuvant endocrine therapy, recurrence remains a challenge, particularly in high-risk patients. Recent trials on cyclin D kinase 4/6 (CDK4/6) inhibitors in adjuvant therapy have shown promise in reducing early recurrence and improving survival. Methods: This review analyzes the clinical evidence supporting the use of CDK4/6 inhibitors, focusing on the NATALEE and monarchE trials, which demonstrate comparable efficacy and manageable safety profiles for ribociclib and abemaciclib. Results and Conclusions: Ribociclib, with its broader applicability and impact on the decision making for axillary lymph node surgery, may be the preferred option in high-risk populations. The review also addresses unanswered clinical questions and highlights the need for ongoing research to optimize the adjuvant therapy strategies.