Colon cancer incidence: recent trends in the United States.

Between 1976-78 and 1985-87, the age-adjusted incidence rates of invasive colon cancer in the United States rose by 15 percent, 3 percent, 21 percent, and 16 percent among White males, White females, Black males, and Black females, respectively. The increases in incidence occurred in all age groups over age 54 and affected each of the major subsites of the colon nearly equally. The larger rates of increase have resulted in higher incidence among Blacks than Whites by the mid-1980s and an increasingly greater excess of this cancer in males. Trends toward earlier diagnosis of invasive colon cancer were found, with increasing rates for localized and regional diseases coupled with stable or decreasing distant-stage disease-rates. The incidence of in situ colon cancer also rose substantially. The findings suggest that changes in diagnostic trends and risk-factor prevalence may be contributing to these patterns, and that the era when colon cancer predominated among White females is clearly over.