Cancer of the corpus uteri in white and black women in Michigan, 1985-1994: an analysis of trends in incidence and mortality and their relation to histologic subtype and stage.

BACKGROUND Cancer of the corpus uteri occurs more commonly among white women in the U.S., yet survival is poorer for black women. This study examined whether this trend has changed and also examined the relation of age and histologic subtype to differences in stage. METHODS This retrospective cohort study assessed incidence trends, mortality trends, and the relation of age and histologic subtype to stage for 12,079 incident cases and 2325 deaths registered between 1985 and 1994 in Michigan. Rate ratios compared incidence and mortality. Odds ratios quantified the contribution of age and histologic subtype to differences in risk for advanced stage, using Mantel-Haenszel univariate techniques and multivariate logistic regression. RESULTS The overall incidence rate was 21.99 per 100,000, and the overall mortality rate was 3.82 per 100,000. Black women had a 40% lower risk (rate ratio [RR] =0.60) of developing cancer of the corpus uteri but had a 54% greater risk (RR=1.54) of dying from cancer of the corpus uteri. Black women were at greater risk of being diagnosed with either sarcoma or more aggressive adenocarcinoma. However, after adjustment for age and histologic subtype, black women still had an increased risk for advanced stage disease (2.63, 95% confidence interval=2.19-3.16). CONCLUSIONS The disparity between white and black women persists in incidence and mortality trends for cancer of the corpus uteri. The greater frequency of more aggressive histologic subtypes experienced by black women accounts for only 10% of their excess risk for more advanced stage disease.