Background Prevalence of non-adherence and non-persistence with adjuvant hormonal therapy for breast cancer is high. This systematic review and meta-analysis aimed to identify the modifiable determinants of adjuvant hormonal therapy medication taking behaviour (MTB) in women with stage I-III breast cancer in clinical practice settings.

Methods We searched PubMed, EMBASE, PsycINFO and CINAHL for articles investigating determinants of adjuvant hormonal therapy MTB. Potentially modifiable determinants were identified and mapped to the 14 domains of the Theoretical Domains Framework (TDF), an integrative framework of theories of behavioural change. Meta-analysis was used to calculate pooled odds ratios for selected modifiable determinants using random effects models.

Results Potentially modifiable determinants were identified in 42 studies and mapped to 9 of the 14 TDF domains. In meta-analysis treatment side-effects (Beliefs about Capabilities) and follow-up care with a general practitioner (vs. oncologist) (Social Influences) were negatively associated with persistence (p < 0.001) and number of medications (Behaviour Regulation) was positively associated with persistence (p < 0.001). Studies did not examine several domains (including Beliefs about Consequences, Intentions, Goals, Social Identity, Emotion and Knowledge) which have been reported to influence MTB in other disease groups.

Discussion This systematic review is the first to examine potentially modifiable determinants of hormonal therapy MTB in women with breast cancer. There is some evidence that the domains Beliefs about Capabilities (side-effects), Behaviour Regulation (managing medication) and Social Influences (follow-up care) influence adherence and persistence with hormonal therapy. Research on medication beliefs, motivation, health care communication and support strategies is needed in order to develop effective interventions to improve hormonal therapy MTB.