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

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.

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.

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%.

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.