Optimizing expectations to prevent side effects and enhance quality of life in breast cancer patients undergoing endocrine therapy: study protocol of a randomized controlled trial

Background: Adjuvant endocrine therapy can improve disease-free survival and time before recurrence in breast cancer patients. However, it is associated with considerable side effects that negatively affect patients' quality of life and cause non-adherence. The recently demonstrated effect of individual expectations on side-effect development (nocebo effect) suggests that psychological factors play a role in the prevention of side effects. The aim of this study is to evaluate cognitive-behavioral side-effect prevention training (SEPT) for breast cancer patients. This article describes the study protocol and applied research methods. Methods/Design: In a randomized controlled trial, 184 female breast cancer patients are assigned to receive either SEPT, standard medical care or a manualized supportive therapy at the start of adjuvant endocrine treatment. SEPT consists of three sessions of cognitive-behavioral training including psychoeducation to provide a realistic view of endocrine therapy, imagination-training to integrate positive aspects of medication into daily life, and side-effect management to enhance expectations about coping ability. Side effects three months after the start of endocrine therapy serve as primary outcomes. Secondary outcomes include quality of life, coping ability and patients' medication adherence. Patients' expectations (i.e., expectations about side effects, coping ability, treatment and illness) are analyzed as mediators. Discussion: The optimization of expectations might be a potential pathway in health care to improve patients' quality of life during long-term medication intake. The results will provide implications for a possible integration of evidence-based prevention training into clinical practice.