Authors' objectives:

The aim of this report is to systematically identify and appraise the international evidence for the effectiveness and costeffectiveness of screening tests for colorectal cancer.

Authors' recommendations: The following conclusions are based on the current evidence available from this report's critical appraisal of literature published since 1997 on the published international evidence for the effectiveness and cost-effectiveness of screening tests for colorectal cancer: High-quality evidence was found that FOBT screening with the guaiac FOBT Haemoccult reduces mortality from CRC. Specifically, evidence from ongoing follow-up for three major RCTs suggests that this mortality reduction has been sustained for the populations in which screening has stopped, but decreased slightly for the population to whom screening has continued to be offered. While less robust, the direct evidence available suggests that a reduction in rectal cancer may be achievable with the use of an immunochemical test. The evidence available since this topic was last considered in New Zealand by the Working Party on Screening for Colorectal Cancer (1998) has not changed substantially. There is limited definitive evidence regarding superior immunochemical FOBT performance over the guaiac tests. However, evidence from cross-sectional studies suggests that the immunochemical test HemeSelect is comparable, or superior, to guaiac testing. Simplified FOB tests may be more acceptable, as there was good evidence that the simplified testing process and sampling kit of the immunochemical test Insure encouraged greater participation rates. The conclusions on this topic should be revisited if further reliable evidence on the comparative performance of screening FOBTs becomes available. International interest in establishing FOBT screening programmes for CRC remains high. Following a pilot screening programme conducted in five regions of the UK using a guaiac test, a national screening programme based on FOB testing for CRC will be introduced by the National Health Service in England from April 2006. Australia is also evaluating FOBT screening in a pilot programme being conducted in three States using two types of immunochemical FOBTs. No large sampled RCT has been completed that provided incidence and mortality data relating to flexible sigmoidoscopy screening. Three large ongoing trials are investigating flexible sigmoidoscopy as either one-off or repeated screening modalities for average-risk men and women aged from their mid-50s. Preliminary results are promising in terms of the feasibility and acceptability of this screening modality, but, long-term incidence and mortality data will not become available for these trials for three to seven years. While the introduction of FS in a national screening programme cannot currently be justified, this recommendation should be reviewed once the results of these trials are available. The generalisability of these findings to the New Zealand population would also need to be considered. A combined screening strategy of FOBT and FS is not supported from the available literature published since 1997. There isinsufficient evidence demonstrating that combined FOBT and FS as a first-line screening strategy in asymptomatic middle-aged populations brings about a greater reduction in CRC incidence and mortality compared to either modality alone. Data on CRC incidence and mortality from a Norwegian trial is expected to become available in late 2007 and this will provide much-needed evidence on the clinical effectiveness of combined screening compared to FS only screening strategies.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://nzhta.chmeds.ac.nz/publications.htm

Year Published: 2007

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: New Zealand

Organisation Name: New Zealand Health Technology Assessment

Contact Address: Department of Public Health and General Practice, Christchurch School of Medicine and Health Sciences, University of Otago, P.O. Box 4345, Christchurch, New Zealand. Tel: +64 3 364 1145; Fax: +64 3 364 1152;

Contact Name: nzhta@chmeds.ac.nz

Contact Email: nzhta@chmeds.ac.nz

Copyright: New Zealand Health Technology Assessment (NZHTA)