Stratified/risk-based screening for colorectal cancer in the UK: an overview.

While colorectal cancer screening is well-established in the UK, at present, it uses a 'one-size fits-all' approach - that is, individual risk is not considered when determining screening regimens (except for some specific conditions such as Lynch syndrome). Stratified screening offers the prospect of directing more intensive screening toward those at higher risk - with a corresponding reduction of screening intensity among lower-risk individuals. Two key opportunities for stratifying colorectal cancer screening are (1) making better use of an individual's quantitative fecal hemoglobin result rather than the current approach of deeming tests to be positive over an arbitrary threshold and (2) gathering information on lifestyle, family history, genetics and other factors to establish risk of colorectal cancer - and using this information to tailor screening regimens. While there is encouraging evidence from modeling studies demonstrating reduced colonoscopy requirements and increased positive prediction of colorectal cancer when incorporating risk assessments within screening, we need 'real world' evidence on stratified screening to establish whether it is effective, improves screening outcomes and is acceptable to the public. We also need to know the impact these changes would have on existing screening programs, and how programs might adapt their organizational and IT processes.