WB: Ovarian Cancer Risk Higher in Both Black and White Women With Endometriosis

A higher risk for ovarian cancer was observed both in Black and White participants with endometriosis.

Prior studies examining the association between endometriosis and leiomyomas (or fibroids) with ovarian cancer risk had been limited to studies of predominantly White women,” explains Holly R. Harris, ScD, MPH. “Given the differing incidence of all three of these conditions between Black and White women, we felt it was important to examine how the associations might differ between the two groups.”

For a study published in Obstetrics & Gynecology, Dr. Harris and colleagues sought to examine the link between endometriosis and fibroids with ovarian cancer risk, with a particular focus on whether the association differed between Black and White participants and whether this link was modified by hysterectomy, oral contraceptive use, or postmenopausal hormone use.

Endometriosis Linked With Greater Risk for Endometriosis & Ovarian Cancer

The study team used data from four case-control studies and two case-control studies within prospective cohorts in the Ovarian Cancer in Women of African Ancestry consortium. A total of 3,124 Black patients and 5,458 White patients participated in the study; 1,008 Black patients and 2,237 White patients had ovarian cancer. The investigators used logistic regression to measure ORs and 95% confidence intervals for links between endometriosis and fibroids with ovarian cancer risk, by race, stratified by histotype and hysterectomy.

Dr. Harris and colleagues found that the incidences of endometriosis and fibroids were 6.4% and 43.2% among Black participants and 7.0% and 21.5% among White participants, respectively. In both racial groups, endometriosis was correlated with a greater risk for endometrioid and clear-cell ovarian cancer (eg, OR for endometrioid tumors for Black and White participants, 7.06 [95% CI, 3.86-12.91] and 2.17 [95% CI, 1.36-3.45], respectively; P_{hetereogeneity}=0.003). “The association between endometriosis and ovarian cancer risk in White participants was stronger in those without hysterectomy, but no difference was observed in Black participants (all P_interaction≥0.05),” Dr. Harris and colleagues write. “Leiomyomas were associated with an elevated risk for ovarian cancer only in those without hysterectomy in both Black (OR, 1.34; 95% CI, 1.11-1.62) and White (OR, 1.22; 95% CI, 1.05-1.41) participants (all P_interaction≥0.05).”

Interventions Can Also Impact Health Outcomes

Conditions such as fibroids and endometriosis can have long-term impacts and medical interventions, such as hysterectomy, which occur due to these conditions and can also impact health outcomes, according to Dr. Harris. “In both Black and White women, having endometriosis or fibroids was associated with a higher risk for ovarian cancer (Figures 1 and 2).”

Given that this is an observational study, she notes, there are no  direct clinical practice implications. “However, the different outcomes we observed between Black and White women, with and without hysterectomy, in terms of ovarian cancer risk indicates clinicians need to reflect on how quality of care impacts health outcomes in these two groups,” she says.

“Almost no research has been done examining the experiences of Black women with endometriosis,” Dr. Harris continues. “We need to keep focusing on this area of research because we know endometriosis increases risk for ovarian cancer as well as a number of other conditions, some of which like lupus and cardiovascular disease, disproportionately impact Black women.”

Dr. Harris and colleagues would like to see further research in this area to help better understand how racial differences in access to care and treatment affect or modify the risk for ovarian cancer.