Declining mortality rates for cancer of the rectum in the United States: 1940-1985.

Abstract

Age-standardized and age-specific mortality rates for cancer of the rectum and cancer of the colon were calculated according to race and gender for 1940-1985; age-standardized rates were calculated according to geographic region for 1950-1980. Mortality rates for cancer of the rectum decreased among white and black people of each gender, in most age categories and all regions of the country. Concurrent with this decline, mortality rates for cancer of the colon increased among all race-gender groups except white females, among whom it decreased. The decline in mortality rates for cancer of the rectum has been largely unappreciated. When deaths occurring from 1940 to 1985 from cancer of the rectum are combined with those from cancer of the colon, mortality rates are increased. However, this combination of sites obscures the divergent trends, which suggest that these cancers have causes that are at least somewhat different.