| [ Summary ] |
There have been accumulated firm evidence for the efficacy of fecal occult blood screening in reducing mortality for colorectal cancer. Four randomized controlled trials (RCTs) were reported which evaluated the efficacy of guaiac-based fecal occult blood test or the Hemoccult test. Consistent results showing mortality reduction for colorectal cancer through the screening programs were reported across the trials. Reported magnitudes of mortality reduction were 33 % for the annual screening program and 13-21 % for biennial programs. A meta-analysis showed 16 % reduced mortality for all programs and 15 % for those employing biennial screening. In addition, incidence reduction was also observed in the population that underwent the screening. Fecal immunochemical testing (FIT) by reversed passive hemagglutination (RPHA) method was developed as a screening test in population-based screening programs and was evaluated for efficacy in terms of mortality reduction in Japan. Although evidence from RCTs is lacking, several observational studies consistently reported reduced mortality from colorectal cancer among those undergoing the RPHA test by 60-80 % as compared with those not undergoing a screening test. Furthermore, sensitivities of RPHA test and other FIT were seen to be higher than that of the Hemoccult test. A RCT showed a doubly higher detection rate of colorectal cancers and advanced adenomas among those who were tested with FIT as compared with those tested with the Hemoccult test, with slight increase in the positivity rate. FIT is now considered to predominate the Hemoccult test in terms of possibly higher magnitude of mortality reduction. |