Screening for colorectal cancer: implications for UK and European initiatives

Colorectal cancer (CRC) is the third most common cancer after lung and prostate cancers, and is the second most common cancer in women in the United Kingdom (UK) after breast cancer. The disease is well suited for prevention with screening programs. CRC is invariably fatal when diagnosed at an advanced stage but curable when diagnosed early, since it passes through a detectable asymptomatic stage. Screening tests with varying degrees of sensitivity and specificity are available. Prior to implementation of a nationwide national programme in the UK, trials are underway to identify the most sensitive and specific screening modality, and to address patient acceptability and resource implications. Screening for CRC using faecal occult blood (FOB) tests may be feasible. There is evidence to show that this modality saves lives at a cost similar to the breast screening programme currently underway in the UK. One-off flexible sigmoidoscopy is an alternative to FOB screening, and pilot data suggest that the technique is logistically feasible in the UK; a multicentre randomised trial is currently underway. Total colonoscopy is the gold standard test, but at present no large randomised controlled trials support this strategy. Colonoscopy is expensive and labour-intensive, and training issues need to be addressed. At the present time, tailored screening (in which intensity is adjusted for individual risk) appears reasonable. FOB and flexible sigmoidoscopy are cost effective but vary in sensitivity and specificity. Public education programmes are essential for any screening strategy to be effective.