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

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. 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. 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. 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.