A comparative analysis of endometrial cancer disparities in incidence, mortality, and survival between women living in Puerto Rico, Non-Hispanic Blacks, Non-Hispanic Whites, and US Hispanics between 2000-2018

Endometrial cancer is the most common gynecologic malignancy and the fourth most common malignancy affecting women in the United States, with 66,200 estimated new cases and 13,030 estimated deaths in 2023. It is among the few cancers with increasing incidence and mortality and is projected to become the 6th most common cancer by 2030. Rising obesity rates parallel increasing endometrial cancer incidence, with national data showing a 1.3% annual percent change in uterine cancer incidence between 2003–2019. Disparities have been documented: when correcting for hysterectomy, Non-Hispanic Black women have the highest incidence and mortality and lower survival compared to White women. Prior Puerto Rico data (1992–2003) showed significantly increasing incidence in Puerto Ricans and NHB, but stable rates for NHW and US Hispanics. Given rising obesity and diabetes—known risk factors—this study evaluates whether women living in Puerto Rico exhibit distinct epidemiologic patterns and disparities compared with NHB, NHW, and Hispanic populations, focusing on incidence, mortality, and survival trends and their variation by age and stage.

The paper references population-based data showing rising uterine cancer incidence in the US with heterogeneous trends across racial/ethnic groups, with the largest increases among Hispanics and other minorities and smaller increases in NHW. Prior literature indicates NHB women have the highest hysterectomy-corrected incidence and mortality and lower survival than White women, with a greater burden of non-endometrioid histologies contributing to mortality. A Puerto Rico study (1992–2003) reported significantly increasing endometrial cancer incidence in Puerto Ricans and NHB but stable rates among NHW and Hispanics. Risk factor literature highlights obesity, diabetes, and reproductive factors (e.g., declining fertility, increased nulliparity) as contributors to rising incidence, with obesity increasingly prevalent in Puerto Rico, including among younger age groups.

Design: Secondary data analysis comparing endometrial cancer incidence, mortality, and survival among women living in Puerto Rico (PR) versus US Non-Hispanic Whites (NHW), Non-Hispanic Blacks (NHB), and Hispanics. Periods: Incidence and mortality (2000–2018); survival (diagnoses 2010–2014 with follow-up through 2019). Data sources: PR incidence from Puerto Rico Central Cancer Registry (PRCCR; ICD-O-3 coding; >95% completeness since 2010); PR mortality from the Demographic Registry of Puerto Rico; US incidence and mortality for NHW, NHB, and Hispanics from NCI SEER Program; population denominators from US Census Bureau Vintage 2019 estimates. Note: SEER data used did not include PR within US estimates; PR data are analyzed separately. PR 2017 incidence cases restricted to January–June due to population change after Hurricane Maria (cases July–December excluded). Population: Women aged ≥20 years with microscopically confirmed primary endometrial carcinoma (ICD-O-3 primary sites C54 Corpus Uteri, C55.9 Uterus NOS; histology codes 8000–8933). Outcomes and measures: - Incidence and mortality rates per 100,000 women aged ≥20, age-adjusted to the 2000 US Standard Population; 95% confidence intervals. - Age groups: 20–34, 35–49, 50–64, 65–79, and ≥80 years. - Stage at diagnosis: localized, regional, distant, unstaged. - Trends quantified via Annual Percent Change (APC) using SEER*Stat and NCI Joinpoint Regression (v4.9.1.0), parametric method with permutation tests; significance at alpha 0.05. Survival: Five-year relative survival rates (RSR) for PR cases diagnosed 2010–2014 (follow-up to 2019); included first primary cases (sequence 0 or 1), microscopic confirmation, ages 20–99.

- Incidence (2014–2018): Puerto Rico had the highest age-adjusted incidence (41.3 per 100,000) among groups; Hispanics had the lowest (34.2). - Age-specific incidence: PR women younger than 65 had higher incidence than NHW, NHB, and Hispanics. APC increases in PR were largest among younger groups: 20–34 years APC 5.02% (p<0.05); 35–49 years APC 6.96% (p<0.05); continued increase in 50–64 years (reported APC ~5.4–5.9%, p<0.05). - Stage distribution (incidence rates per 100,000, 2014–2018): PR had lowest distant stage incidence (2.1) compared with NHW (3.1), Hispanics (3.6), NHB (6.7); PR had highest localized stage incidence (27.5) versus NHW (27.3), Hispanics (22.8), NHB (20.7). - Mortality (2000–2018 aggregate rates): NHB had the highest overall mortality (12.5 per 100,000). PR and NHW had similar overall mortality (6.8 and 6.4, respectively); Hispanics lower (5.7). - Age-specific mortality: In ages 20–34 and 35–49, PR women had the highest mortality rates (0.6 and 3.2 per 100,000, respectively), with significant increasing APC in PR ages 35–49 (2.08%, p<0.05). After age 50, NHB mortality exceeded other groups, peaking at ages 65–79 (49.5 per 100,000). - Mortality trends: Significant increases in mortality for NHB ages 35–49 (APC 3.15%, p<0.05); significant increases also for PR, NHW, and Hispanics in this age group. Hispanics had greatest increases at ages 50–64 (rate 8.3; APC 2.57%, p<0.05); NHW increased at ages 65–79 (rate 22.5; APC 2.46%, p<0.05). - Survival in PR (diagnosed 2010–2014; follow-up to 2019): Overall 5-year RSR 79.9% (95% CI 78.09–81.63). By stage: localized 90.0%; regional 69.67%; distant 23.04%; unstaged 69.44%. PR overall 1-year RSR 91.80%; 3-year RSR 82.91%.

The findings indicate that women in Puerto Rico experience higher incidence of endometrial cancer at younger ages (20–64) compared to NHW, NHB, and Hispanics, suggesting earlier-life risk exposures. Elevated obesity prevalence in Puerto Rico, including among younger women, and increasing duration of obesity may contribute to earlier onset. Declining fertility and increased nulliparity may further increase estrogen exposure and risk. Despite PR’s lower distant-stage incidence and higher localized-stage incidence—factors associated with better outcomes—young PR women (20–49) still exhibit higher mortality than peers in other groups, pointing to possible health disparities, including access to care, socioeconomic factors, higher obesity burden at younger ages, and potential biological differences influencing tumor aggressiveness. NHB women continue to bear the highest overall mortality and more distant-stage diagnoses, consistent with known disparities. The observed PR 5-year survival (~79.9%) is slightly improved from earlier PR estimates but remains close to, and slightly below, recent US averages, underscoring ongoing disparities and the need for targeted prevention and early detection efforts in PR, particularly among younger women.

Women in Puerto Rico had the highest and rising endometrial cancer incidence from 2000 to 2018 compared to NHW, NHB, and US Hispanics, with particularly elevated incidence and mortality below age 50. PR women also presented more often with localized disease and less often with distant disease than other groups. The results highlight critical disparities affecting younger Puerto Rican women, likely linked to obesity and reproductive trends, among other factors. Future research should examine histologic subtypes, obesity and metabolic risk trajectories, hysterectomy prevalence, biomarkers, and quality-of-life impacts, and evaluate access-to-care and early detection strategies tailored to the PR population.

- Incidence and mortality analyses were not corrected for hysterectomy prevalence, potentially biasing rate comparisons across groups. - Puerto Rico SEER-linked datasets with race/ethnicity were not available; PR was analyzed separately from US SEER groups. - PR 2017 incidence data included only January–June due to post–Hurricane Maria population shifts, which may affect trend estimates. - Survival analyses were limited to PR cases (2010–2014 diagnoses) with follow-up to 2019; cross-group survival comparisons were not performed. - As a secondary data analysis, residual confounding (e.g., BMI, comorbidities, socioeconomic status, access to care) and lack of detailed tumor biology data may affect interpretations. - Small numbers in some younger age strata may impact stability of APC estimates.