Non-adherence to adjuvant endocrine therapy (ET) for breast cancer (BC) is common. Our goal was to determine the associations between psychosocial factors and ET non-persistence. We recruited women with BC receiving care in an integrated healthcare system between 2006 and 2010. Using a subset of patients treated with ET, we investigated factors related to ET non-persistence (discontinuation) based on pharmacy records (≥90 days gap). Serial interviews were conducted at baseline and every 6 months. The Functional Assessment of Cancer Therapy (FACT), Medical Outcomes Survey, Treatment Satisfaction Questionnaire (TSQM), Impact of Events Scale (IES), Interpersonal Processes of Care measure, and Decision-making beliefs and concerns were measured. Multivariate models assessed factors associated with non-persistence. Of the 523 women in our final cohort who initiated ET and had a subsequent evaluation, 94 (18 %) were non-persistent over a 2-year follow-up. The cohort was primarily white (74.4 %), stage 1 (60.6 %), and on an aromatase inhibitor (68.1 %). Women in the highest income category had a lower odds of being non-persistent (OR 0.43, 95 % CI 0.23-0.81). Quality of life and attitudes toward ET at baseline were associated with non-persistence. At follow-up, the FACT, TSQM, and IES were associated with non-persistence (p < 0.001). Most women continued ET. Women who reported a better attitude toward ET, better quality of life, and more treatment satisfaction, were less likely to be non-persistent and those who reported intrusive/avoidant thoughts were more likely to be non-persistent. Interventions to enhance the psychosocial well-being of patients should be evaluated to increase adherence.
Keywords: Adherence; Breast cancer; Psychosocial factors; Quality of life.