QLTI-04. LINKING DATA FROM A BRAIN CANCER CLINICAL REGISTRY (BRAIN) WITH THE STATE-BASED REGISTRY OF BIRTHS DEATHS MARRIAGES: IMPROVING THE QUALITY OF CLINICAL REGISTRY SURVIVAL DATA

Abstract BACKGROUND Real-world data (RWD) collected routinely in clinical care forms the basis of cancer clinical registries. These registries are inclusive and provide valuable research outcomes, however missing data particularly survival compromise the accuracy of RWD. Here we explore the utility of data linkage to state-based registries to enhance the capture of survival outcomes. METHODS We reviewed prospectively collected data from consecutive patients with brain tumours in the Brain Tumour Registry Australia Innovation and Translation (BRAIN) database and included those treated in Victoria with no recorded date of death and no follow-up the preceding 6 months. Full name and birthdate were used to match patients in the BRAIN registry to those in the Victorian Births, Deaths and Marriages (BDM) Registry. Survival outcomes were compared, pre- and post-data linkage (DL). RESULTS Of the 7735 patients contained in BRAIN, 5435 patients (70.3%) met eligibility criteria and had no recorded date of death. 1611 (30%) of patients were matched with a date of death in BDM. More matches were found in tumours of highest malignant potential such as grade 4 glioma (67.2%), brain metastases (63.9%) and primary cerebral lymphoma (50.5%), compared with good-prognostic tumours such as meningioma (8.7%) and schwannoma (3.2%). Compared to post-DL, survival outcomes were significantly overestimated pre-DL for the entire cohort (30.3m vs 17m, p< .0001). This difference was most pronounced for Grade-3 glioma (93.7m vs. 38.1 p = 0.008) but significant differences were seen across all tumour types. CONCLUSION Using an Australian brain-tumour population, this is the first study to demonstrate the importance of improved RWD accuracy through linking state-based registries to comprehensive cancer registries. This missing death data significantly compromises the potential quality of audit and research projects, driving a repeated over-estimate of survival. Routine periodic DL to pertinent registries should be considered to ensure accurate reporting and interpretation of RWD.