%0 Journal Article %A Yin Zhou %A Fiona M Walter %A Luke Timothy Allan Mounce %A Gary A Abel %A Hardeep Singh %A William Hamilton %A Grant D Stewart %A Georgios Lyratzopoulos %T Identifying opportunities for timely diagnosis through patterns of primary care tests in patients with bladder and renal cancer: a longitudinal linked data study %D 2021 %R 10.3399/BJGP.2021.0282 %J British Journal of General Practice %P BJGP.2021.0282 %X Background: Understanding pre-diagnostic test use could reveal diagnostic windows where more timely evaluation for cancer may be indicated. Aim: To examine pre-diagnostic patterns of results of abnormal blood tests in bladder and renal cancer patients. Design and setting: Retrospective cohort study using primary care and cancer registry data on bladder and renal cancer patients diagnosed between 2012-2015 in England. Method: We examined the rates of patients with a first abnormal result in the year before diagnosis, for “generic” (full blood count components, inflammatory markers, calcium) and “organ-specific” blood tests (creatinine, liver function test components) which may lead to subsequent detection of incidental cancers. We used Poisson regression, to detect the month during which the cohort’s rate of each abnormal test started to increase from baseline, and examined the proportion of patients with a test found in the first half of the window, as these ‘early’ tests might represent opportunities where further evaluation could be initiated. Results: Data from 4,533 bladder and renal cancer patients were analysed. The monthly rate of patients with a first abnormal test increased towards the time of cancer diagnosis. Abnormalities of both generic and organ-specific tests started to increase from 6-8 months pre-diagnosis, with 25-40% of these patients having an abnormal test in the “early half” of the diagnostic window. Conclusion: Population-level signals of bladder and renal cancer can be observed in abnormalities in commonly performed primary care blood tests up to 8 months before diagnosis, indicating the potential for earlier diagnosis in some patients. %U https://bjgp.org/content/bjgp/early/2021/10/19/BJGP.2021.0282.full.pdf