We aimed to systematically review barriers/facilitators of adherence among adolescents with cancer (aged 10-24 years), following a comprehensive approach to adherence that goes beyond medication-taking. Empirical studies published in English exploring determinants of adherence to medical recommendations among adolescents with cancer were identified in MEDLINE, PsycInfo, and Web of Science, up to October 2021. Records and full-text articles were reviewed by two independent reviewers, and results were classified according to the World Health Organization's (WHO) multidimensional adherence model. Eighteen studies were included. Despite heterogeneity in the definition and measurement of adherence, literature supported barriers/facilitators at patient, treatment, condition, healthcare team/system, and social/economic levels. Specifically, patient-related factors (i.e., psychological functioning and beliefs about disease and treatment) and social-related factors (i.e., family functioning) were major determinants of adolescent adherence. Few studies were conducted, and inconsistent findings were displayed for other dimensions (i.e., healthcare team/system, treatment, and condition-related factors). Adherence is a complex and multidetermined phenomenon. More research is needed to provide critical insights for policymakers and healthcare professionals in planning practices and interventions that effectively address meaningful barriers/facilitators of adolescents' adherence.
Keywords: Adherence; adolescent; cancer; compliance; determinants.