Abstract 2285: Risk factors for endometrial cancer in black and white women: A pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2).
Authors: Cote Michele L. , Alhajj Tala , Ruterbusch Julie J. , Brinton Louise A. , Blot William J. , Chen Chu , Henderson Brian E. , Horn-Ross Pamela L. , Kolonel Laurence N. , Rebbeck Timothy R. , Setiawan Veronica W. , Signorello Lisa B. , Simon Michael S. , Weiss Noel S. , Wentzensen Nico , Yang Hannah P. , Olson Sara H. 
Published: August 2014

Introduction: More than 47,000 women will be diagnosed with endometrial cancer in 2012, making it the most common gynecologic cancer among women in the United States. Data from the SEER registry from 1975-2009 report the incidence rate of endometrial cancer is lower among black women than white women (19.2 and 27.5 cases per 100,000 women, respectively). Tumor histology also varies by racial group, with a larger proportion of black women diagnosed with non-endometrioid tumors compared to their white counterparts. It is possible that risk factors for endometrial cancer may differ between black and white women; the small number of black women in individual studies has precluded these analyses. The aim of this study was to investigate risk factors for endometrial cancer in blacks using a pooled analysis. For comparison, we pooled data on risk factors among non-Hispanic white women in the same studies.

Methods: We have data from eleven studies that included &gt;10 black cases and &gt;10 black controls (7 cohort studies and 4 case-control studies). The following information was collected from each study: age at diagnosis/study entry, education, body mass index (BMI), smoking status, reproductive variables, hormone use, and self-reported diabetes and hypertension. Unconditional logistic regression was used to estimate odds ratios and 95% confidence intervals for each risk factor in blacks and whites separately. Estimates for endometrioid tumors will also be presented.

Results: Data were pooled for 2,011 black women (516 cases and 1,495 controls) and 19,297 white women (5,693 cases and 13,604 controls). In univariate analyses, the following variables were associated with endometrial cancer in both black and white women: BMI, smoking, oral contraceptive use for 10 years or more, and diabetes. In models adjusted for these variables, along with age and study site, obesity (BMI ≥ 30) was associated with an approximate 3-fold increase in risk for both black and white women (OR=2.80, 95% CI: 2.00, 3.92 and OR=3.26, 95% CI: 2.96, 3.59, respectively). Diabetes was also associated with a 30-40% increase in risk among both groups. Cigarette smoking was associated with reduced risk of endometrial cancer among both blacks and whites (OR=0.66, 95%CI: 0.47, 0.94 and OR=0.62, 95% CI: 0.54, 0.71, respectively). Increasing parity was more strongly associated with decreased risk in whites (p-trend &lt;0.001) than blacks (p-trend = 0.09). Similarly, age at first birth was also more protective in whites (p-trend&lt;0.001) than blacks (p-trend=0.76).

Conclusions: Overall, risk factors for endometrial cancer are similar in black and white women, with the exception of some of the reproductive factors, which do not appear to afford protection in blacks to the same extent as in whites.

Citation Format: Michele L. Cote, Tala Alhajj, Julie J. Ruterbusch, Louise A. Brinton, William J. Blot, Chu Chen, Brian E. Henderson, Pamela L. Horn-Ross, Laurence N. Kolonel, Timothy R. Rebbeck, Veronica W. Setiawan, Lisa B. Signorello, Michael S. Simon, Noel S. Weiss, Nico Wentzensen, Hannah P. Yang, Sara H. Olson. Risk factors for endometrial cancer in black and white women: A pooled analysis from the Epidemiology of Endometrial Cancer Consortium (E2C2). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2285. doi:10.1158/1538-7445.AM2013-2285