Influence of Patient and Treatment Factors on Adherence to Adjuvant Endocrine Therapy in Breast Cancer

PURPOSE/OBJECTIVES: To comprehensively assess the patient and illness or treatment factors that may predict nonadherence to adjuvant endocrine therapy and to explore whether an interaction occurs between these factors in women with breast cancer. DESIGN: Repeated-measures design. SETTING: The Outpatient Services of the Women's Cancer Program at the University of Pittsburgh Cancer Institute and participants' homes. SAMPLE: 91 women with early-stage breast cancer who received endocrine therapy. METHODS: Adherence was assessed continuously for the first 18 months of endocrine therapy. Patient and illness or treatment factors were assessed at four time points (Time 1 to Time 4). Time 1 (baseline) was within two weeks prior to the initiation of endocrine therapy. Times 2-4 occurred at six-month intervals, as many as 18 months after Time 1. MAIN RESEARCH VARIABLES: Adherence, patient factors, and illness or treatment factors. FINDINGS: Adherence to endocrine therapy declined significantly during the first 18 months of treatment in women with breast cancer. The presence of negative mood and symptoms before starting treatment predicted nonadherence to endocrine therapy over time. Perceptions of financial hardship, symptoms, disease stage, and more complex medication regimens intensified the effect of negative mood on adherence over time. CONCLUSIONS: Women with breast cancer may be at risk for nonadherence to prescribed endocrine therapy if they experience depression or anxiety and symptoms prior to initiating therapy. IMPLICATIONS FOR NURSING: Oncology nurses should be alert to women with breast cancer who are depressed or anxious or who are experiencing symptoms. Management of negative mood and symptoms may result in better adherence.