Behavioral Interventions to Enhance Adherence to Hormone Therapy in Breast Cancer Survivors: A Systematic Literature Review

Adjuvant hormone therapy contributes to reductions in recurrence and mortality for women with hormone receptor-positive breast cancer. However, adherence to hormone therapy is suboptimal. This is the first systematic literature review examining interventions aimed at improving hormone therapy adherence. Researchers followed the PRISMA guidelines. PubMed-Medline, CINAHL, PsychInfo, Ovid-Medline, and EMBASE were searched for behavioral interventions that aimed to enhance adherence to adjuvant hormone therapy in breast cancer survivors. A total of 376 articles were screened for eligibility. Five articles met the study criteria. All interventions presented adherence outcomes after 1-year follow-up. None significantly enhanced adherence compared to the usual care in the primary analysis (odds ratios ranged from 1.03 to 2.06 for adherence and from 1.11 to 1.18 for persistence). All studies targeted patients, and only 3 studies included postmenopausal breast cancer patients. Three tested the same intervention consisting of educational materials. Only one was conducted in the United States. Only one reported participants' ethnicity. Overall, it was unclear whether the studies contained bias. The use of different terminology and operationalization of adherence made comparisons challenging. Interventions to improve adherence to adjuvant hormone therapy in US breast cancer populations that include survivors who are ethnically diverse, premenopausal, and receiving tamoxifen therapy are necessary to inform future interventions. Adoption of consistent adherence definitions/measurements will provide a clearer framework to consolidate aggregate findings. Given the limited efficacy of tested interventions, it is important to engage oncologists and researchers to develop approaches that target different components associated with hormone therapy adherence, such as doctor-patient communication or social support.