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.