Elsevier

Annals of Epidemiology

Volume 10, Issue 2, February 2000, Pages 97-105
Annals of Epidemiology

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

https://doi.org/10.1016/S1047-2797(99)00039-3Get rights and content

Abstract

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.

Introduction

The incidence of endometrial cancer rose in some populations between 1950 and the early 1970s, possibly as a result of increased prescribing of postmenopausal estrogen replacement therapy 1, 2, 3. By contrast, the incidence of this condition remained relatively constant in Olmsted County, Minnesota, between 1945 and 1975 (4). This may have been a reflection of the relatively low level of postmenopausal estrogen use in this community, although endometrial cancer was associated with estrogen replacement therapy here (4), as elsewhere.

Data from the Surveillance, Epidemiology and End-Results (SEER) program revealed a subsequent 27% decline in the incidence of endometrial cancer in the United States between 1975 and 1986 (5). Hemminki and coworkers (6) reported that the number of prescriptions for estrogens in the United States declined during the same period and then increased, but with a concomitant increase in progestin prescriptions as well. This decrease in the use of unopposed estrogen replacement therapy parallels the decline in uterine cancer and supports an association between the two. Given recent emphasis on the protective effects of estrogen on osteoporosis and coronary heart disease (CHD), it is of interest to identify trends for endometrial cancer in this community since 1974. Consequently, we updated the earlier report to include the new cases of endometrial cancer diagnosed in 1975 through 1991. Using identical methods, we reevaluated risk factors for endometrial cancer and assessed changes in survival over time.

Section snippets

Methods

Population-based epidemiologic research can be conducted in Olmsted County, MN, because medical care is virtually self-contained within the community (7). Most cancer care, for example, is provided by the Mayo Clinic, which has maintained a common medical record system with its two large affiliated hospitals in the community (St. Marys and Rochester Methodist) for over 90 years. The Mayo Clinic dossier-type record, thus, contains both inpatient and outpatient data, and specific records are

Incidence Study

During the 17-year study period, 1975–1991, a total of 117 Olmsted County women were newly diagnosed with endometrial cancer. In addition, we found a case that should have been included in the 1970–1974 time period and added it to the earlier data set. Conversely, re-review of the histologic slides indicated that three cases from the 1945-1974 study appeared to have adenocarcinoma with zones of uterine sarcoma. Since these three cases did not meet current criteria, they were deleted. For the

Discussion

After declining between 1950 and 1974, the incidence of endometrial cancer among Olmsted County women rose in 1975–1984 only to fall again in 1985–1991. Although the incidence rates by year vary considerably due to small numbers, it is of interest to point out that the rates follow the increase in estrogen use as determined by the number of prescriptions (6) and show a decrease after progesterone was introduced as combined treatment with estrogen. The average annual age-adjusted (1970 United

Acknowledgements

This work was supported in part by research grant AR30582 from the National Institutes of Health, United States Public Health Service. The authors would like to thank Mrs. Mary Roberts for typing the manuscript.

References (42)

  • L.D Marrett et al.

    Trends in the incidence of cancer of the corpus uteri in Connecticut, 1964–1979, in relation to consumption of exogenous estrogen

    Am J Epidemiol.

    (1982)
  • D.F Austin et al.

    The decreasing incidence of endometrial cancerPublic health implications

    Am J Public Health.

    (1982)
  • SEER Stat 2.0 CD-ROM: SEER Cancer Incidence Public-Use Database, 1973–1996. Issued April 1999. Bethesda, MD: National...
  • E Hemminki et al.

    Prescribing of noncontraceptive estrogens and progestins in the United States, 1974–86

    Am J Public Health.

    (1988)
  • L.T Kurland et al.

    The patient record in epidemiology

    Sci Am.

    (1981)
  • W.T Creasman

    New gynecologic cancer staging

    Obstet Gynecol.

    (1990)
  • Pokras V, Hufragel V. Hysterectomies in the United States, 1965–84. In: Vital & Health Statistics, Data from the...
  • E.J Bergstralh et al.

    Calculating incidence, prevalence and mortality rates for Olmsted County, MinnesotaAn Update

    (1992)
  • Breslow NE, Day NE. Statistical Methods in Cancer Research. v. 2. The Analysis of Case-Control Studies. Lyon: IARC...
  • P Bruzzi et al.

    Estimating the population attributable risk for multiple risk factors using case-control data

    Am J Epidemiol.

    (1985)
  • E.L Kaplan et al.

    Non-parametric estimation from incomplete observations

    J Am Stat Assoc.

    (1958)
  • Cited by (14)

    • Synchronous primary cancers of the endometrium and ovary in young women: A Korean Gynecologic Oncology Group Study

      2013, Gynecologic Oncology
      Citation Excerpt :

      In our large data set of 471 endometrial cancer patients younger than 40 years, 43 patients (9.1%) had coexisting ovarian malignancy at the time of the primary surgery: there were 21 patients (4.5%) with synchronous ovarian cancer and 22 patients (4.7%) with primary endometrial cancer metastatic to the ovary. This finding was similar to the population-based study performed in patients under 40 years of age with endometrial cancer [24]: the incidences of coexisting ovarian malignancy and synchronous ovarian cancer were 9.4% and 3.1%, respectively. Lynch syndrome (hereditary nonpolyposis colorectal cancer; HNPCC) is an autosomal-dominant cancer predisposition syndrome that increases risk for multiple cancers, including colon, endometrial, and ovarian cancer.

    • Incidence and factors associated with synchronous ovarian and endometrial cancer: A population-based case-control study

      2012, Gynecologic Oncology
      Citation Excerpt :

      This study was approved by the Mayo Clinic and Olmsted Medical Center Institutional Review Boards (IRBs). The previous REP studies by McDonald et al. and Beard et al. were used to identify all patients with EC, including synchronous EC and epithelial OC cases, diagnosed between January 1, 1945 and December 31, 1991 [18,19]. Germ cell tumors and granulosa cell tumors were excluded.

    • Gynaecological cancers in Umbria (Italy): Trends of incidence, mortality and survival, 1978-1998

      2004, European Journal of Obstetrics and Gynecology and Reproductive Biology
    View all citing articles on Scopus
    View full text