Factors influencing 5-year persistence to adjuvant endocrine therapy in young women with breast cancer

Although younger age has been negatively associated with persistence to adjuvant endocrine therapy (ET), factors contributing to non-persistence remain poorly understood. We assessed factors associated with non-persistence to ET and described the 5-year trajectories of quality of life (QoL) and symptoms in young women (≤40 years) with hormone receptor-positive breast cancer (BC).We retrieved data on clinical characteristics and non-persistence from the medical annual records in the European cohort of the "Helping Ourselves, Helping Others: The Young Women's BC Study" (IBCSG 43-09 HOHO). Women completed surveys at baseline, biannually for three years, and annually for another seven years. Data collection included sociodemographic information, QoL aspects assessed by the Cancer Rehabilitation Evaluation System-Short Form and symptoms assessed by the Breast Cancer Prevention Trial symptom scales. Cox regression models were applied to identify factors associated with non-persistence.The cumulative risk of interrupting ET within 5 years was 27.7 % (95 % CI, 21.5-35.2). The QoL subscale scores remained stable over 5 years, with slight improvements in the physical subscale. Hot flashes decreased (p