Timing of Dose Reductions and Survival Outcomes in Metastatic Breast Cancer Patients Treated with CDK4/6 Inhibitors
Author Information
Author(s): Kubilay Tolunay Pınar, Kurt İnci Bediz, Usta Şura, Topkaç Ali, Karabuğa Berkan, Aydemir Ergin, Öner İrem, Akay Hacan Büşra, Ateş Öztürk, Karaçin Cengiz, Yalçıntaş Arslan Ülkü
Primary Institution: Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital, University of Health Sciences, Ankara, Turkey
Hypothesis
This study aims to evaluate the impact of the timing of dose reductions on progression-free survival (PFS) and overall survival (OS) in a real-world cohort.
Conclusion
Early dose reductions in CDK4/6 inhibitors negatively affect PFS and OS, while late dose reductions are associated with better outcomes.
Supporting Evidence
- Patients who underwent dose reductions within the first three months had an mPFS of 14.26 months.
- Those who had dose reductions after three months had an mPFS of 33.12 months.
- Patients without any dose reductions had an mPFS of 20.6 months.
- The median overall survival (mOS) was not reached for patients who underwent dose reductions at any time.
- Patients who had dose reductions within the first three months had an mOS of 37.12 months.
- Patients who did not undergo any dose reduction had an mOS of 57.76 months.
- Hematological toxicity, primarily neutropenia, was the most common cause of dose reductions.
Takeaway
If patients with breast cancer need to lower their medication dose early on, it can make their treatment less effective, but if they lower it later, it might not hurt their chances as much.
Methodology
This single-center, retrospective study included patients treated with ribociclib or palbociclib between 2019 and 2023, analyzing dose reductions and survival outcomes.
Potential Biases
The retrospective nature of the study may lead to selection bias.
Limitations
The study's retrospective design may introduce biases, and it excluded patients starting treatment at a reduced dose and those with treatment durations of less than 3 months.
Participant Demographics
The mean age of participants was 57.13 years, with 67.1% treated in the first-line setting.
Statistical Information
P-Value
p<0.001
Confidence Interval
95% CI: 29.04–33.77
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
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