Adherence to oral anti-neoplastic agents, an overview and meta-analysis

BACKGROUND: The use of oral anti-neoplastic therapies has accelerated in recent years. Non-supervised administration of oncological therapies introduces uncertainty in regard to adherence. This review and meta-analysis reports on available literature relating to adherence, adherence measuring methods, interventions to improve adherence and estimates patient adherence to common oral anti-neoplastic therapies. METHOD: A literature search was conducted in the PubMed database up to January 29, 2024 using relevant terminology for oral anti-neoplastic agents. Titles and abstracts of retrieved articles were screened, and full-text articles deemed of interest were reviewed. Studies suitable for meta-analysis and consistent with the analytical approach were selected based on adherence measurement methods and definitions. Random effects meta-analysis was conducted using the R package metafor and visualized with forest plots for cumulative adherence and lower-bound adherence separately. RESULTS: We identified eight reviews and 75 original studies on adherence to non-endocrine oral anti-neoplastic agents, spanning the years from 1987 to 2023, with the vast majority published from 2010 onward. This review estimates the cumulative adherence to oral anti-neoplastic agents to be 84% (95% CI 78-89) and lower-bound adherence as 71% (95% CI 63-78). CONCLUSION: The definition of non-adherence and the measurement methods used across studies vary, rendering the comprehensive understanding of the subject challenging. This review identifies an adherence rate that deviates from full compliance across a wide variety of treatment regimens and tumor types, which could provide valuable insights for healthcare professionals in optimizing patient management.