Evaluation of Dose Reduction Factors and Impact on Progression-Free Survival in Patients Treated with CDK 4/6 Inhibitors.

CDK 4/6 inhibitors are effectively utilized among patients with hormone-positive, HER-2-negative metastatic breast cancer. The dose reduction for these patients varies between 35% and 57% across multiple trials. We aim to clarify the characteristics of patients who had dosage reduction and the effect of this reduction on survival outcomes.