Adherence to adjuvant endocrine therapy among White British and ethnic minority breast cancer survivors in the United Kingdom

Objective: Around half of women do not take adjuvant endocrine therapy (AET) as prescribed. Research suggests that adherence rates vary across ethnic groups. This study compared AET adherences rates in White British women and women from minority ethnic groups in the United Kingdom. Methods: This is an observational study with 2001 breast cancer survivors recruited from outpatient clinics. Eligible women were diagnosed with primary breast cancer and prescribed AET within the last 3 years. Adherence was measured using the Medication Adherence Rating Scale. Eligible women were asked to complete a questionnaire pack that collected sociodemographic data such as age, relationship status and ethnicity. Independent samples t tests and χ ² tests were used to compare White British women and women from minority ethnic groups on self-reported adherence to AET. Results: Of White British women, 27.8% were classed as non-adherent, compared to 44.4% of women from minority ethnic groups. A logistic regression controlling for relevant demographics indicated that women from minority ethnic groups had a significantly higher risk of non-adherence than women who were White British (odds ratio = 1.50, p = 0.03). Conclusion: Rates of non-adherence to AET are higher in women from minority ethnic groups, which may contribute towards racial disparities in breast cancer outcomes. Research with larger and more diverse samples is needed to explore this further and to investigate the psychosocial factors driving differences in adherence.