Evaluation of the G8 Questionnaire and the Groningen Frailty Indicator to Predict Toxicities of CDK 4/6 Inhibitors in Older Breast Cancer Patients?

CDK 4/6 inhibitors (palbociclib, ribociclib) have taken their place in our practice recently with their clinical benefits in the treatment of hormone-positive and HER2 negative metastatic breast cancer. Abemaciclib, another CDK 4/6 inhibitor, is not frequently preferred because of reimbursement problems in Turkey. The most obvious advantages of CDK 4/6 inhibitors are that they are used orally and have relatively fewer side effects against chemotherapy. Neutropenia, diarrhea, elevation in liver function tests are the main dose-limiting side effects. In the geriatric age group, it can be thought that the expected benefit from the treatment will not be achieved in cases where these side effects cannot be predicted or managed well. The geriatric age group (65 years and older) deserves special attention in oncology practice, considering both the treatments and the disease itself. Although a number of very useful clinical scales have been developed regarding this subject, it is important that the scale used should be comprehensive as well as being easily applicable for integrating it into daily practice. Geriatric 8 (G8) was found to be a highly sensitive test based on a comprehensive geriatric examination, while the Groningen frailty scale with high specificity. The common feature of these two tests is that they are suitable for daily practice as they are easy to fill. In the light of this information, we aimed to examine whether the G8 and Groningen frailty scale could shed light on clinicians in predicting side effects during the use of CDK 4/6 inhibitors (palbociclib and ribociclib) in geriatric breast cancer patients. We also aimed to reveal the adverse events of these CDK 4/6 inhibitors as real-life experience.