%0 Journal Article
%T The risk of colorectal cancer with symptoms at different ages and between the sexes: a case-control study
%A William Hamilton
%A Robert Lancashire
%A Debbie Sharp
%A Tim J Peters
%A KK Cheng
%A Tom Marshall
%J BMC Medicine
%D 2009
%I BioMed Central
%R 10.1186/1741-7015-7-17
%X This was a case-control study using pre-existing records in a large electronic primary care database. Cases were patients aged 30 years or older with a diagnosis of colorectal cancer between January 2001 and July 2006, matched to seven controls by age, sex and practice. All features of colorectal cancer recorded in the 2 years before diagnosis were identified. Features independently associated with cancer were identified using multivariable conditional logistic regression, and their risk of cancer quantified.We identified 5477 cases, with 38,314 age, sex and practice-matched controls. Six symptoms and two abnormal investigations (anaemia and microcytosis) were independently associated with colorectal cancer. The positive predictive values of symptoms were: rectal bleeding, positive predictive value for a male aged ¡Ý 80 years 4.5% (95% confidence interval 3.5, 5.9); change in bowel habit 3.9% (2.8, 5.5); weight loss 0.8% (0.5, 1.3); abdominal pain 1.2% (1.0, 1.4); diarrhoea 1.2% (1.0, 1.5) and constipation 0.7% (0.6, 0.8). Positive predictive values were lower in females and younger patients. Only 27% of patients had reported either of the two higher risk symptoms.Most symptomatic colorectal cancers present with only a low-risk symptom. There is a need to find a method of identifying those at highest risk of cancer from the large number presenting with such symptoms.Over 35,000 colorectal cancers were diagnosed in England in 2004 [1]. Survival in the UK is worse than in other European countries and the US, partly because of later presentation in the UK [2]. Delays in presentation to medical care and diagnosis have been observed in several studies [3].Early diagnosis may reduce mortality. The relative risk of death from colorectal cancer is between 0.67 and 0.85 following faecal occult blood screening [4]. A large UK prospective study of screening in half a million patients aged 50 to 69 years found 2% to be faecal occult blood (FOB) positive, of whom 11% had colorect
%U http://www.biomedcentral.com/1741-7015/7/17