Disparities in hysterectomy-corrected endometrial cancer incidence trends by histologic subtype among racial/ethnic groups in California, 2012-2019.

Background: Hysterectomy-corrected endometrial cancer incidence among racial/ethnic minority groups by histologic subtype and age group has not been well studied. To examine recent trends in hysterectomy-corrected endometrial cancer rates among California women by histologic subtype, race/ethnicity, and age group.

Methods: We estimated hysterectomy prevalence from the Behavioral Risk Factor Surveillance System. Hysterectomy-corrected age-standardized endometrial cancer incidence rates (per 100,000 women) by endometrioid and non-endometrioid subtypes, age at diagnosis, and race and ethnicity from 2012 to 2019 were calculated using California Cancer Registry data. Incidence rates and annual percentage changes (APC) were estimated.

Results: Among endometrioid subtypes, American Indian women had the highest incidence (62.9 per 100,000). Incidence rates also significantly increased among Asians/Pacific Islanders (1.69 %), with an increase of 7.14 % and 7.39 % for women aged 45-54 and 55-64, respectively, though these did not reach statistical significance. In addition, Hispanics had an increased incidence rate (3.02 %) from 2012 to 2019, with a particularly sharp rise (18.42 %) observed in Hispanics aged 25-34 years between 2016 and 2019. For non-endometrioid subtypes, non-Hispanic Blacks had the highest incidence (29.4 per 100,000), with the ≥65 age group showing an upward trend (9.39 % increase from 2012 to 2016) before significantly declining by 8.16 % from 2017 to 2019. American Indians had the second-highest incidence (14.1 per 100,000), but no significant trend was observed, likely due to the small sample size of this population.

Conclusions: Our findings show that race/ethnicity is associated with endometrial cancer incidence and underscore the importance of jointly examining racial/ethnic disparities with age and histologic subtype.