Abstract PS4-08-28: Patient-reported outcomes of adjuvant therapy with CDK4/6 inhibitors for HR+/HER2- early breast cancer: a retrospective cohort study

Abstract Objective To compare the patient-reported outcomes (PROs) and quality of life in patients with HR+/HER2- early breast cancer (EBC) treated with ribociclib (RIB) and abemciclib (ABE) as adjuvant therapy. Methods A multicenter, retrospective cohort study was conducted in Chinese patients receiving ribociclib or abemciclib as adjuvant therapy for HR+/HER2- EBC. PRO data were collected via an electronic questionnaire. The questionnaire was based on the PRO scale for breast cancer patients in China (NCC-BC-A scale), EQ-5D-5L and safety information of CDK4/6 inhibitors, including six dimensions of physiological function, psychological status, social support, treatment related symptoms, economic dimension and overall self-evaluation. The higher score of the questionnaire, the better quality of life. Results Between Mar 15, and May 12, 2025, 197 patients completed the survey, including 94 patients who received ribociclib and 103 patients who received abemciclib. Overall, 195 patients (99%) were female and two (1%) were male. No difference was observed in baseline characteristics such as age, employment status, medical insurance, and concomitant treatment. The total score of the PRO in ribociclib group was higher than that in abemciclib group (187.14±17.57 vs 180.66±22.26, p=0.024). In therapeutic domain, the score was significantly higher in ribociclib group (34.81±5.29 vs 32.77±5.51, p=0.009). Patients in ribociclib group were less affected by the treatment-related symptoms of diarrhea (3.88±0.53 vs 2.31±1.33, p0.001), fatigue (2.29±0.91 vs 2.00±1.02, p=0.038) and hair loss (2.94±1.39 vs 2.49±1.24, p=0.018). The proportion of patients receiving ribociclib who discontinued due to the side effects of long-term treatment (28.6% vs 50%) or reduced the dose due to adverse events (22.2% vs 70%) was lower. The overall health status score of ribociclib group was higher (6.67±1.27 vs 5.83±1.45, p0.001). Conclusion HR+HER2- EBC patients who received ribociclib had a better PRO score than those who received abemciclib. Patients in ribociclib group experienced less treatment-related adverse reactions, especially diarrhea, fatigue, and hair loss, and had a lower rate of discontinuation/reduction due to adverse events, a better self-evaluation of their overall health status. Citation Format: B. Cong, C. Hou, C. Shan, S. Sun, S. Sun, Y. Wang. Patient-reported outcomes of adjuvant therapy with CDK4/6 inhibitors for HR+/HER2- early breast cancer: a retrospective cohort study abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-08-28.