A systematic scoping review of interventions to optimise medication prescribing and adherence in older adults with cancer

Background: Older adults with cancer often require multiple medications (polypharmacy) comprising cancerspecific treatments, supportive care medications (e.g. analgesics), and medications for pre-existing health conditions. Increasing numbers of medications may increase risks of potentially inappropriate prescribing and nonadherence. Objective: To provide an overview of evaluations of interventions aimed at optimising medication prescribing and/or adherence in older adults with cancer. Methods: A systematic scoping review was undertaken. Four databases (PubMed, EMBASE, CINAHL, PsycINFO) were searched using relevant search terms (e.g. cancer, older adults). Eligible studies evaluated interventions seeking to improve medication prescribing and/or adherence in older adults (>= 65 years) with cancer using a comparative evaluation. All outcomes for studies that met inclusion criteria were included in the review. Extracted data were collated using tables and accompanying narrative descriptive summaries. The review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. Results: Nine studies met inclusion criteria comprising five randomised controlled trials (RCTs) and four beforeand-after study designs. Studies were primarily conducted in oncology clinics, ranging from single study sites to 109 oncology clinics. Sample sizes ranged between 33 and 4844 patients. Interventions most commonly involved patient education (n = 6) delivered by pharmacists or nurses. Three studies reported on prescribing-related outcomes and seven studies reported on adherence-related outcomes, using different terminology and assessment methods. Prescribing-related outcomes focused on medication appropriateness (using Beers criteria) and drug-related problems including drug interactions. Adherence-related outcomes included assessments of selfreported medication adherence and calculation of patients' medication possession ratio. Conclusions: This scoping review highlights a lack of robust evaluations of interventions aimed at optimising medication prescribing and adherence in older adults with cancer. Future research should improve rigour during intervention development, evaluation and reporting in order to generate findings that could inform future practice.