Endometrial Cancer in Olmsted County, MN: Trends in Incidence, Risk Factors and Survival

PURPOSE: We updated an earlier study in this community from 1945–1974 in order to assess trends in the incidence of, risk factors for, and survival from endometrial cancer in 1975–1991. METHODS: Incidence rates were based on all new cases of endometrial cancer diagnosed among Olmsted County, Minnesota, women during the years 1975–1991, with the population denominator from decennial census data. Risk factors were assessed with conditional logistic regression comparing the incidence cases to age- and gender-matched controls with intact uteri seen the same year the case was diagnosed. Survival was assessed using the Kaplan-Meier method. RESULTS: The incidence of endometrial cancer (age-adjusted to 1970 United States total) in 1975–1991 was 14.3 per 100,000 person-years, which is slightly increased from 1965–74. The rate was 21.7 per 100,000 person-years after adjustment for hysterectomy prevalence. As in the previous study, conjugated estrogen use for six months or more (odds ratio [OR] 2.71; 95% confidence interval [CI] 1.14–6.46) and body mass index (OR 1.06; 95% CI 1.01–1.11) increased the risk of endometrial cancer. The five-year relative survival rate (82%) was not improved over the earlier study. CONCLUSIONS: A small increase in endometrial cancer incidence was linked to the same risk factors identified in an earlier study in this community. No improvement in survival was seen.