Off-label drug use in oncology: a systematic review of literature

Abstract

What is known and objective: The off-label use of medicines is widespread in several diseases. This type of prescribing practice is particularly more acute in oncology. However, the suitability of anticancer medications for off-label use remains an issue of controversy, due to uncertainty around the clinical benefits and potential toxicities, limited evidence to support clinical decision-making, increased out-of-pocket costs for patients and ethical concerns around the lack of informed consent. Currently, data pertaining to the global prevalence of off-label use in cancer therapy are lacking. The aim of this review was to provide an overview of off-label drug use prevalence in oncology. Methods: A systematic literature search was performed in PubMed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines from 1975 to 2016. Studies assessing the prevalence of off-label use of anticancer drugs were included. Data synthesis: Of the 199 eligible papers retrieved, 23 studies were included in this systematic literature review. Off-label drug use in inpatients ranged from 18% to 41%. Among adult patients with cancer, 13%–71% received a minimum of one off-label chemotherapy. The main reasons for off-label drug use were ‘drug unapproved for specific tumour’ and ‘modified drug applications’. Among adults, metastatic cancers and palliative care patients received the most off-label drugs. The off-label drug use unsupported by standard treatment guidelines or drug compendia was in the range of 7%–31%. Conclusion: Off-label drug use in cancer therapy is commonly practised but outcomes could vary significantly. Hence, greater scrutiny and robust clinical guidance is needed to establish the favourable benefit–risk ratio for patients at the time of prescribing at each level of oncology care to facilitate rational off-label prescribing.