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

Purpose: 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). Methods: 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. Results: 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 < 0.001), while vaginal problems intensified (p < 0.001) over time. Being married without children and having difficulties interacting and communicating with the medical team were significantly associated with non-persistence. Conclusions: Discussing the desire to conceive with partnered childless women and establishing a good relationship with the medical team may be important in addressing the non-persistence in young BC survivors. As recent data suggests the safety of pausing ET to conceive, this approach may be a reasonable future option to limit non-persistence.