Patricia G. Moorman

Racial Differences in Population Attributable Risk for Epithelial Ovarian Cancer in the OCWAA Consortium

Abstract Background The causes of racial disparities in epithelial ovarian cancer (EOC) incidence remain unclear. Differences in the prevalence of ovarian cancer risk factors may explain disparities in EOC incidence among African American (AA) and White women. Methods We used data from 4 case-control studies and 3 case-control studies nested within prospective cohorts in the Ovarian Cancer in Women of African Ancestry Consortium to estimate race-specific associations of 10 known or suspected EOC risk factors using logistic regression. Using the Bruzzi method, race-specific population attributable risks (PAR) were estimated for each risk factor individually and collectively, including groupings of exposures (reproductive factors and modifiable factors). All statistical tests were 2-sided. Results Among 3244 White EOC cases and 9638 controls and 1052 AA EOC cases and 2410 controls, AA women had a statistically significantly higher PAR (false discovery rate [FDR] P < .001) for first-degree family history of breast cancer (PAR = 10.1%, 95% confidence interval [CI] = 6.5% to 13.7%) compared with White women (PAR = 2.6%, 95% CI = 0.8% to 4.4%). After multiple test correction, AA women had a higher PAR than White women when evaluating all risk factors collectively (PAR = 61.6%, 95% CI = 48.6% to 71.3% vs PAR = 43.0%, 95% CI = 32.8% to 51.4%, respectively; FDR P = .06) and for modifiable exposures, including body mass index, oral contraceptives, aspirin, and body powder (PAR = 36.0%, 95% CI = 21.0% to 48.8% vs PAR = 13.8%, 95% CI = 4.5% to 21.8%, respectively; FDR P = .04). Conclusions Collectively, the selected risk factors accounted for slightly more of the risk among AA than White women, and interventions to reduce EOC incidence that are focused on multiple modifiable risk factors may be slightly more beneficial to AA women than White women at risk for EOC.

Genital Powder Use and Risk of Epithelial Ovarian Cancer in the Ovarian Cancer in Women of African Ancestry Consortium

Abstract Background: Genital powder use is more common among African-American women; however, studies of genital powder use and ovarian cancer risk have been conducted predominantly in White populations, and histotype-specific analyses among African-American populations are limited. Methods: We used data from five studies in the Ovarian Cancer in Women of African Ancestry consortium. Participants included 620 African-American cases, 1,146 African-American controls, 2,800 White cases, and 6,735 White controls who answered questions on genital powder use prior to 2014. The association between genital powder use and ovarian cancer risk by race was estimated using logistic regression. Results: The prevalence of ever genital powder use for cases was 35.8% among African-American women and 29.5% among White women. Ever use of genital powder was associated with higher odds of ovarian cancer among African-American women [OR = 1.22; 95% confidence interval (CI) = 0.97–1.53] and White women (OR = 1.36; 95% CI = 1.19–1.57). In African-American women, the positive association with risk was more pronounced among high-grade serous tumors (OR = 1.31; 95% CI = 1.01–1.71) than with all other histotypes (OR = 1.05; 95% CI = 0.75–1.47). In White women, a significant association was observed irrespective of histotype (OR = 1.33; 95% CI = 1.12–1.56 and OR = 1.38; 95% CI = 1.15–1.66, respectively). Conclusions: While genital powder use was more prevalent among African-American women, the associations between genital powder use and ovarian cancer risk were similar across race and did not materially vary by histotype. Impact: This is one of the largest studies to date to compare the associations between genital powder use and ovarian cancer risk, overall and by histotype, between African-American and White women.

Race Differences in the Associations between Menstrual Cycle Characteristics and Epithelial Ovarian Cancer

Abstract Background: Menstrual cycle characteristics—including age at menarche and cycle length— have been associated with ovarian cancer risk in White women. However, the associations between menstrual cycle characteristics and ovarian cancer risk among Black women have been sparsely studied. Methods: Using the Ovarian Cancer in Women of African Ancestry (OCWAA) Consortium that includes 1,024 Black and 2,910 White women diagnosed with epithelial ovarian cancer (EOC) and 2,325 Black and 7,549 White matched controls, we investigated associations between menstrual cycle characteristics (age at menarche, age at menstrual regularity, cycle length, and ever missing three periods) and EOC risk by race and menopausal status. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Results: Black women were more likely to be <11 years at menarche than White women (controls: 9.9% vs. 6.0%). Compared with ≥15 years at menarche, <11 years was associated with increased EOC risk for White (OR = 1.25; 95% CI, 0.99–1.57) but not Black women (OR = 1.10; 95% CI, 0.80–1.55). Among White women only, the association was greater for premenopausal (OR = 2.20; 95% CI, 1.31–3.68) than postmenopausal women (OR = 1.06; 95% CI, 0.82–1.38). Irregular cycle length was inversely associated with risk for White (OR = 0.78; 95% CI, 0.62–0.99) but not Black women (OR = 1.06; 95% CI, 0.68–1.66). Conclusions: Earlier age at menarche and cycle irregularity are associated with increased EOC risk for White but not Black women. Impact: Associations between menstrual cycle characteristics and EOC risk were not uniform by race.

Racial disparities in epithelial ovarian cancer survival: An examination of contributing factors in the Ovarian Cancer in Women of African Ancestry consortium

AbstractBlack women diagnosed with epithelial ovarian cancer have poorer survival compared to white women. Factors that contribute to this disparity, aside from socioeconomic status and guideline‐adherent treatment, have not yet been clearly identified. We examined data from the Ovarian Cancer in Women of African Ancestry (OCWAA) consortium which harmonized data on 1074 Black women and 3263 white women with ovarian cancer from seven US studies. We selected potential mediators and confounders by examining associations between each variable with race and survival. We then conducted a sequential mediation analysis using an imputation method to estimate total, direct, and indirect effects of race on ovarian cancer survival. Black women had worse survival than white women (HR = 1.30; 95% CI 1.16‐1.47) during study follow‐up; 67.9% of Black women and 69.8% of white women died. In our final model, mediators of this disparity include college education, nulliparity, smoking status, body mass index, diabetes, diabetes/race interaction, postmenopausal hormone (PMH) therapy duration, PMH duration/race interaction, PMH duration/age interaction, histotype, and stage. These mediators explained 48.8% (SE = 12.1%) of the overall disparity; histotype/stage and PMH duration accounted for the largest fraction. In summary, nearly half of the disparity in ovarian cancer survival between Black and white women in the OCWAA consortium is explained by education, lifestyle factors, diabetes, PMH use, and tumor characteristics. Our findings suggest that several potentially modifiable factors play a role. Further research to uncover additional mediators, incorporate data on social determinants of health, and identify potential avenues of intervention to reduce this disparity is urgently needed.

Racial Differences in the Tumor Immune Landscape and Survival of Women with High-Grade Serous Ovarian Carcinoma

Abstract Background: Tumor-infiltrating lymphocytes (TIL) confer a survival benefit among patients with ovarian cancer; however, little work has been conducted in racially diverse cohorts. Methods: The current study investigated racial differences in the tumor immune landscape and survival of age- and stage-matched non-Hispanic Black and non-Hispanic White women with high-grade serous ovarian carcinoma (HGSOC) enrolled in two population-based studies (n = 121 in each racial group). We measured TILs (CD3+), cytotoxic T cells (CD3+CD8+), regulatory T cells (CD3+FoxP3+), myeloid cells (CD11b+), and neutrophils (CD11b+CD15+) via multiplex immunofluorescence. Multivariable Cox proportional hazard regression was used to estimate the association between immune cell abundance and survival overall and by race. Results: Overall, higher levels of TILs, cytotoxic T cells, myeloid cells, and neutrophils were associated with better survival in the intratumoral and peritumoral region, irrespective of tissue compartment (tumor, stroma). Improved survival was noted for T-regulatory cells in the peritumoral region and in the stroma of the intratumoral region, but no association for intratumoral T-regulatory cells. Despite similar abundance of immune cells across racial groups, associations with survival among non-Hispanic White women were consistent with the overall findings, but among non-Hispanic Black women, most associations were attenuated and not statistically significant. Conclusions: Our results add to the existing evidence that a robust immune infiltrate confers a survival advantage among women with HGSOC; however, non-Hispanic Black women may not experience the same survival benefit as non-Hispanic White women with HGSOC. Impact: This study contributes to our understanding of the immunoepidemiology of HGSOC in diverse populations.