Longitudinal Trends in Illness Perception and Depression during Adjuvant Breast Cancer Endocrine Therapy: A Prospective Observational Study

This study aimed to identify the changes in the illness perceptions and depression of women with breast cancer, undergoing AET, at three time points (i.e., before initiating AET, 3 months follow-up, and 12 months follow-up). We investigated the interaction effects of their demographic and clinical characteristics on illness perception changes over time. Furthermore, factors including the patient's characteristics and illness perceptions associated with depressive symptoms 1 year after starting AET were explored. Illness perception and depressive symptoms were assessed with the brief illness perception questionnaire and the Center for Epidemiologic Studies Depression Scale, in a prospective study of 150 women. The changes in illness perceptions and depression between the three time points were analyzed using repeated measures ANOVA. The factors associated with depressive symptoms were identified using regression analysis. Illness perception improved overall over the 12 months. However, more patients perceived their illness as chronic, experienced more symptoms, and developed negative beliefs that treatment could not control their disease. Patients' depressive symptoms decreased significantly. Depression at the baseline, cancer stage, and the perception of personal control were highly associated with depression after 12 months. These findings suggest that healthcare providers should offer appropriate interventions to patients, for managing symptoms, having a positive belief that treatment can control their disease, and preventing long-term depressive symptoms.