Which tool is best for colorectal cancer screening?

Colorectal cancer screening programmes have now been introduced or are about to be launched in many European countries, Australia, and New Zealand. In the United States, screening for colorectal cancer has long been actively promoted by the medical community and patient organisations. Evidence from randomised controlled trials has been an absolute requirement for introducing new techniques in many fields of medicine, and screening is no exception.1 Until recently, the only screening tool that has been proved to be effective in reducing mortality from colorectal cancer is faecal occult blood testing.2

The results of the UK Flexible Sigmoidoscopy Screening Trial were published recently.3 This multicentre randomised controlled trial investigated the effect of one off sigmoidoscopy screening on the incidence of and mortality from colorectal cancer. More than 170 000 people aged 55-64 years were randomised to flexible sigmoidoscopy screening or no screening. The screening took place at 14 centres throughout the United Kingdom between 1994 and 1999, and 71% of people who were invited attended the screening. In the intention to treat analysis, after 11 years of follow-up people invited to screening had a significantly reduced incidence of colorectal cancer (absolute difference 35 cases; hazard ratio 0.77, 95% confidence interval 0.70 to 0.84) and mortality from colorectal cancer …