A Systematic Review of Methods to Measure Adherence to Oral Anticancer Medications in African Women With Breast Cancer at Initiation, Implementation, and Discontinuation of Therapy

Background This systematic review was aimed at assessing methods used to measure oral anticancer medication (OAM) adherence at its three phases (initiation, implementation, and discontinuation) in women with breast cancer (BC) in Africa. Methods This review followed the Joanna Briggs Institute guidelines. Four databases were searched from 1990 to 2025 using keywords representing medication adherence, oral anticancer agents, breast cancer, measures, women, and Africa. The reporting followed the updated PRISMA guidelines. Results All 13 studies (100%) reviewed assessed OAM adherence at the implementation phase, four studies (30.8%) at the discontinuation phase, and one study (7.7%) at the initiation phase. Persistence was also assessed in four studies (30.8%). Prescription refill records were used to measure adherence at the initiation phase. Drug assays in blood, prescription refills, pill counts, medical records reviews, and self‐report measures were used during the implementation phase. Prescription refills, medical records, and self‐report measures were used at the discontinuation phase. Overall, self‐report measures (46.2%; n = 6) were the most frequently used during the implementation phase. However, most studies that employed these measures did not report the psychometric properties, including reliability and validity. Conclusions The implementation phase was the most commonly assessed. Initiation and discontinuation phases were relatively less assessed. Self‐report measures were the most frequently used, but the reliability and validity of these measures are lacking, hence limiting the evidence to guide practice. Thus, measures with sound psychometric properties, including reliability and validity, that can assess OAM adherence across its three phases are needed to improve adherence measurement and patient outcomes, particularly in Africa.