Motivational Interviewing Counseling to Increase Endocrine Therapy Adherence in Diverse Patients

Background: Oral endocrine therapy (ET) is an inexpensive and effective therapy for hormone receptor-positive (HR+) breast cancer that prevents recurrence but relies upon long-term adherence for up to ten years. More than 80% of breast cancer patients have an HR+ phenotype and are candidates for ET, but approximately half discontinue or become non-adherent by five years. ET underuse is more prevalent in Black and young (18 years old, English speaking, and with stage I–III HR+ breast cancer. Participants were recruited across a large academic medical center and four community sites. Feasibility and acceptability were assessed by measures of participant recruitment, retention, session participation, and patient-reported satisfaction. ET adherence at 12 months was assessed by self-report and medication event monitoring system (MEMS) caps using a continuous measure of the proportion of days covered (PDC) as well as a dichotomous measure of the optimal adherence, defined as >80% PDC. Results: Forty-two women initiated the intervention, of whom thirty-five participants (83%) completed outcome assessments at 12 months, including thirteen Black and twenty-two non-Black participants. The average participant age was 54.8 years (range: 25–73). Overall, 97% completed at least three MI sessions and 83% completed at least four sessions. Participant retention and satisfaction were high, particularly among Black women. Self-reported adherence at 12 months was 88% overall (100% in Black women and 81% in non-Black women). The majority of women also achieved 80% of days adherent using MEMS caps, with a greater adherence in Black women. Conclusions: This study demonstrates the feasibility, acceptability, and early promise of the effectiveness of an MI counseling-based intervention to promote ET adherence and prevent breast cancer recurrence in diverse populations