Abstract

Aim: Although metastatic breast cancer cannot be completely cured, overall survival is currently over three years. It is known that 5-year survival is around 20% in the patient population over the age of 75. There are overall survival times exceeding 50 months in the general population with CDK4/6 inhibitors. In the elderly patient group, CDK4/6 inhibitors sometimes cannot be used under optimal conditions due to intolerable side effects. For this reason, survival times may be shortened. This study aimed to investigate the effect of the use of CDK4/6 inhibitors on survival in the patient group over the age of seventy-five.

Method: Patients over the age of seventy-five, metastatic, hormone receptor positive, HER2 negative, and using CDK4/6 inhibitors who were followed up and treated in our center were included in this study. Demographic data of the patients and the data necessary to calculate survival times were recorded through the hospital data processing center and death notification system. Kaplan Meier and Log-rank tests were used in the survival findings of the patients.

Results: A total of 26 patients were included in the study. Except for one male patient, the remaining patients were female. It was observed that 81% of the patients did not receive chemotherapy before CDK4/6 inhibitor. 57% of the patients were CERB2 negative and there was no difference in survival between CERB2 1+ and 2+ patients. 53% of the patients presented with de-novo metastatic disease, and 62% of the patients had both bone and visceral organ metastases at the time of admission. It was determined that 61% of the patients used palbociclib, while the rest used ribociclib, and 73% of the patients used CDK4/6 inhibitors in the first step. During the follow-up period, 42% of patients developed progressive disease. 9 of the 10 patients who died had visceral organ metastases. The progression-free survival of the general population after CDK4/6 inhibitor was 23.8 months, while the overall survival time was 26.1 months. The overall survival time, calculated based on the date of diagnosis of the patients, was found to be 77.8 months.

Conclusion: It was found that the progression-free survival time of the elderly patient population was 1-2 months shorter compared to literature data, and the overall survival time was approximately 14 months longer.

Keywords: Breast cancer, CDK4/6 inhibitors,  Elderly patient