REVIEW Colon Cancer : An Approach from Molecular Epidemiology

The number of colon cancer death in 1990 was 7,791 (6% of all deaths) in males and 7,718 (8% of all deaths) in females in Japan. Both incidence and mortality rates of colon cancer is steadily increasing in Japan both in males and females, although that of rectal cancer remained stationally (Fig. The incidence rate of colon cancer in 1985, adjusted to modified 1985 population in Japan, was 24.3/100,000 for males and 17.2/100,000 for females, and that of rectal cancer was 17.2 for males and 10.7 for females. The mortality rate of colon cancer was 10.8 and 8.3, and that of rectal cancer was 8.9 and 4.9, in males and females respec-tively2-5). As a result of the introduction of massscreening program for colon cancer in 1992, the incidence of colon cancer should be expected to rise further by early detection of borderline cases such as minute carcinomas in adenomas6). The natural progression of the latter has not been fully established, and it is not known if these minute carcinomas regress spontaneously7).