| [ Summary ] |
Mortality reduction is the only indicator for the effectiveness of mass screening. Randomized controlled trial (RCT) is considered the ideal method to evaluate mortality rates in mass screenings. The effectiveness of colorectal cancer screening, using fecal occult blood test (FOBT) was evaluated in three RCTs and case-control studies. Immunochemical FOBT exhibits better accuracy compared to chemical tests. Since colorectal cancer has long preclinical intervals, repeated screenings may increase the program sensitivity.
Compliance with diagnostic examinations after a FOBT is an important factor to sustain the effectiveness of screening, although in Japan the mean compliance rate is less than 60 percent. Research concerning related factors and measures to improve the status of testing should be carried out. Moreover, accuracy control in mass screenings should be implemented because FOBT positive rates and compliance with diagnostic examinations exhibit a negative relationship. An optimal positive rate of FOBT should be also considered. To achieve these objectives, an information network connecting primary screening providers, caretakers, and hospitals, where diagnostic examinations and therapeutic procedures are performed, is essential. Colon cancer screening systems involve all procedures from FOBT to therapies for colorectal cancer as well as search for false negative cases. Through these processes, the effectiveness of screening may be assessed. |