Healthcare Systems Data (HSD) to Improve the Efficiency of Clinical Trials Within the UK: A Prospectively Planned Comparison of HSD and Trial-Reported Outcomes Within the Add-Aspirin Cancer Clinical Trial

AIMS: Healthcare systems data (HSD) can potentially improve the efficiency and costs of clinical trials (CTs) and reduce the burden of follow-up. To be used in CTs, HSD need to be accessible, accurate and complete. We compared data from trial-specific case-report forms (CRFs) with relevant HSD to assess whether HSD could replace hospital-based follow-up within an ongoing CT. MATERIALS AND METHODS: Add-Aspirin (NCT02804815) is a multicentre, randomised, basket trial evaluating aspirin after potentially curative cancer therapy in four tumour types. The primary outcome measure is disease-free survival. HSD obtained from the English National Cancer Registration and Analysis Service (NCRAS) included initial cancer diagnosis and staging, recurrence, specific adverse events, and mortality for English participants during the first 3 years of the trial and was compared to CRF data collected at participating centres. Tabulations and descriptive statistics were used to assess agreement and explore differences between the datasets. RESULTS: HSD was obtained for 3188/3538 (90%) of English participants. Tumour staging for all four tumour groups generally had good concordance, though this was variable (ranging from 85% (Cohen's weighted kappa = 0.32) to 99% (kappa = 0.84)) and was lower with neoadjuvant therapy and/or radical radiotherapy. HSD identified all CRF-reported deaths and some further deaths not in the trial database due to loss to follow-up or lag time in data submission. Cancer registry recurrence data captured