The CAPER studies: five case-control studies aimed at identifying and quantifying the risk of cancer in symptomatic primary care patients.

PublishedJournal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: This paper reviews the background to five primary care case-control studies, collectively known as the CAPER studies (Cancer Prediction in Exeter). These studies, on colorectal, lung, prostate and brain tumours, sought to identify the particular features of cancer as reported to primary care. They also sought to quantify the risk of cancer for symptoms and primary care investigations, both individually and paired together. METHODS: Two studies were on colorectal cancer: the former with 349 cases used hand searching and coding of entries, while the latter obtained 6442 cases from a national electronic database. The lung and prostate studies had 247 and 217 cases, respectively, and used manual methods. The brain study also used a national electronic database, which provided 3505 cases. RESULTS: Generally, the symptoms matched previous series from secondary care, though the risks of cancer, expressed as positive predictive values, were lower. Rectal bleeding in colorectal cancer, and haemoptysis in lung cancer both had positive predictive values of 2.4%. The risk of a brain tumour with headache was one in a thousand. INTERPRETATION: The results identify areas where current guidance on urgent referral for investigation of suspected cancer could be improved.The CAPER studies would not have been possible without the co-operation of Devon practices and their staff – they are remarkably welcoming. Thanks also go to the GP Research Database (brain) and the Health Improvement Network (anaemia), plus the Dendrite cancer registry in Exeter whose staff were – and continue to be – most helpful. Three research assistants deserve particular mention for their quality of work, plus endless enthusiasm: Sally Stapley, Cath Stabb and Jackie Barrett. The five studies were funded by the Department of Health through the Policy Research Programme (colon, lung and prostate), by the now defunct NHS Research General Practices Scheme (brain), and by the Bobby Moore Fund of Cancer Research UK (anaemia). WH also received research fellowships though NIHR Coordinating Centre for Research Development and Royal College of General Practitioners/BUPA awards, and through a Walport Fellowship. Ethics approvals were Exeter Local Research Ethics Committee (REC) (colon, lung and prostate), the Independent Scientific Advisory Committee (brain) and London Multi-centre REC (anaemia)