# Real-World Quality-of-Life Data in Metastatic Breast Cancer Patients Treated with CDK4/6 Inhibitors Using Four Assessment Tools

## TL;DR

This study evaluates the quality of life of metastatic breast cancer patients using four tools and finds that CDK4/6 inhibitors and comorbidities significantly affect their well-being.

## Contribution

The study is the first in Europe to use four distinct tools to assess quality of life in real-world metastatic breast cancer patients on CDK4/6 inhibitors.

## Key findings

- Ribociclib is associated with better sleep quality and fewer insomnia problems compared to other CDK4/6 inhibitors.
- Mental fatigue and loss of appetite are linked to poorer patient survival.
- Comorbidities are associated with lower quality of life, including increased fatigue, insomnia, and stress.

## Abstract

Patients with breast cancer endure psychological and physical symptoms that negatively impact their quality of life. This study underscores the importance of addressing the needs of metastatic breast cancer patients through four assessment tools that evaluate the patient from different perspectives: general quality of life, depression/anxiety/stress, fatigue, and sleep quality. To the best of our knowledge, this is the only study in Europe to utilize four distinct evaluation instruments to assess quality of life in a real-world context for patients with metastatic breast cancer undergoing treatment with CDK4/6 inhibitors. Our findings demonstrate that the quality of life for these patients is affected in various ways, particularly in their physical, social, and role functioning. Consequently, we encourage all medical oncologists to incorporate quality of life evaluation tools into their daily practice.

Purpose: To evaluate the impact of the type of CDK4/6 inhibitor administered and comorbidities on the quality of life in patients with metastatic breast cancer, as well as the correlation between quality of life and patient outcomes. Materials and Methods: This prospective single-center study utilized four internationally validated questionnaires: the EORTC QLQ-C30 (European Organization for Research and Treatment of Cancer Core Cancer Quality of Life Questionnaire), the Depression, Anxiety, and Stress Scale-21 (DASS-21), the Multidimensional Fatigue Inventory (MFI), and the Pittsburgh Sleep Quality Index (PSQI), administered to a cohort of 76 patients undergoing treatment for metastatic breast cancer with CDK4/6 inhibitors. Results: Ribociclib is associated with fewer insomnia problems and appears to provide better sleep quality compared to other CDK4/6 inhibitors. Mental fatigue and loss of appetite negatively influence patient survival. Patients with comorbidities reported more severe insomnia and constipation. Comorbidities are associated with a lower quality of life, reflected in greater fatigue, insomnia, and constipation, as well as increased scores for depression and stress. Conclusions: Assessing global quality of life in metastatic breast cancer patients is essential, as it can predict patient progression and should be integrated into every breast cancer unit.