Innovative Solutions for Clinical Trial Follow-up: Adding Value from Nationally Held UK Data.

Clinical trials provide the data that underpin evidence-based oncological practice. Over and above their primary outcome measures, collected and analysed by the clinical trials unit, trials provide an opportunity to generate a wide range of additional information over a prolonged period of time. Nationally held data have potential to facilitate longer term follow-up and explore associated toxicities and downstream consequences and in the UK include data from secondary care, including hospital episode statistics, national chemotherapy and radiotherapy datasets and primary care records. Specific to use in oncological practice, the National Cancer Data Repository contains linked data from a variety of sources for patients with a diagnosis of cancer, both cancer and non-cancer related. The challenge of using these data in clinical trials relates to the need to extract identifiable patient data, with the associated ethical and legal issues. The data access processes are time consuming and require evidence of information governance compliance. This overview article reviews the current data available, the current and potential uses both within and outside clinical trials and the challenges encountered in the process of acquiring data. We focus specifically on the use of nationally held data for non-cancer outcomes, including toxicity and associated conditions.