Beliefs and attitudes toward endocrine therapy in patients with hormone receptor-positive breast cancer.

Patients' beliefs about medications are important predictors of medication adherence; however, the relationship between patient beliefs and adjuvant endocrine therapy (AET) adherence in patients with breast cancer remains unclear. In this study, we aimed to determine the association between patient beliefs and adherence to AET. Self-reported questionnaires covering necessity beliefs (NB), concerns beliefs (CB), and adherence were completed by 210 Korean patients with breast cancer. The rate of nonadherence was determined by calculating necessity-concern (N-C) differentials and attitudinal subgroup analysis. Multivariate logistic regression analysis was performed to determine the independent impact of patient beliefs on nonadherence. Nonadherence (Morisky Medication Adherence Scale < 8) was reported in 74.3% ( = 156) of patients and predicted by a negative balance regarding AET [odds ratio (OR) = 0.89; 95% confidence interval (CI): 0.83-0.96] and strong concerns about AET such as those in the Ambivalent (OR = 5.41; 95% CI: 1.84-15.92) and Skeptical (OR = 3.48, 95% CI: 1.14-10.65) subgroups. Patient beliefs are significantly associated with adherence to AET in Korean patients with breast cancer. NB, CB, and N-C differentials may be useful intervention targets to improve medication adherence.