Abstract
Simultaneous multisitic cancer screening is a key task in multipha-sic health testing and services in Japan. Among the cancers of various sites detected by current standard test methods, colorectal cancer detected by the 2-day immunological fecal occult blood test has one of the highest detection rates among cancers of all sites and is one of the easiest cancers from whichhhcer detected by the 2-day immunological fecal occult blood test has one of the highest detection rates among cancers of all sites and is one of the easiest cancers from which to save the patient as judged by 5-year cumulative survival rates after detection. Thus, given such low-cost, low-risk, and precise immunological test methods, we conclude that colorectal cancer is one of the cancers that is most suited to secondary prevention. Qualitative assays have been the main type of fecal occult blood test, but in recent years quantitative assays have also come to be used. It is possible to predict the degree of progression of the detected cancer from the positive pattern in the 2-day qualitative test, and from the hemoglobin concentration in addition to the positive pattern in the quantitative test. These methods are promising as a means to move away from the vagueness of group tests toward predictions for individual cancer cases in cancer screening.
