Abstract A55: Place of residence modifies racial/ethnic disparities in the incidence of endometrial cancer.

Background: The Agency for Healthcare Research and Quality of the US Department of Health and Human Services notes that healthcare quality problems are reflected in a wide variation in the use of health care services. Endometrial cancer is the most common gynecologic malignancy in the United States. Incidence varies with age and race/ethnicity and is most common among post-menopausal and White women. Describing regional variations in incidence rates can help to address disparities through better understanding and may also facilitate allocation of healthcare resources.

Methods: The NCI's Surveillance, Epidemiology, and End Results (SEER) dataset was queried to identify all 92,857 women diagnosed with endometrial cancer from 2000-2009 in the 16 geographically determined registries included in this study. Average annual age-adjusted incidence rates (per 100,000 women) were calculated and adjusted for race/ethnicity, and age < or ≥ to 60 years and compared between the regional registries. The “Non-Hispanic White” population was compared to “Other” including women of all other races/ethnicities, which were combined since the incidence of endometrial cancer was similar for black, Hispanic, and women of other races/ethnicities.

Results: For women of all ages combined, there was no significant difference in incidence between Non-Hispanic Whites and Others in the Hawaii registry; in all other registries, the incidence in Non-Hispanic White women significantly exceeded the incidence in Others. The greatest disparity was seen in Iowa, where the incidence in Non-Hispanic Whites was 14.4/100,000 cases higher. The least disparity was seen in Louisiana (1.7/100,000 excess cases). Among women < 60 at diagnosis, Hawaii is the lone registry in which women of other race/ethnicity have a higher incidence than Non-Hispanic White women. The greatest disparity in women less than 60 was in Iowa (7.3/100,000 excess cases) and the smallest significant disparity was in the California (excluding SJ/LA/SF) registry (1.4/100,000 excess cases). For women 60 or older at diagnosis, only in the Greater Georgia and Louisiana registries did the incidence in Others exceed the incidence in Non-Hispanic Whites. Of the 14 remaining registries, 13 had significantly higher incidence in Non-Hispanic White women. The greatest disparity was in Iowa, where incidence in Non-Hispanic Whites was 50.4/100,000 cases higher. The least disparity in women diagnosed 60 or older was in the Atlanta registry (9.5/100,000 excess cases). The only registry with no incidence disparity in women 60 and older was Kentucky.

Conclusions: We found geographic location greatly modifies racial and ethnic disparities in the incidence of endometrial cancer, regardless of age. This, as yet, unexplained variation in racial/ethnic disparity based on geography merits further study to identify causative factors as well as to help guide rational allocation of healthcare resources.

Citation Format: Travis-Riley K. Korenaga, Kristy K. Ward, Michael T. McHale, Cheryl C. Saenz, Steven C. Plaxe. Place of residence modifies racial/ethnic disparities in the incidence of endometrial cancer. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr A55.