Non-invasive test misses more than four times the number of endometrial cancer cases in Black women than with white counterparts.
Transvaginal ultrasound (TVUS), the screening typically used to identify women who might have endometrial cancer, is not an effective tool for screening Black women.
In a study published July 15 in JAMA Oncology, investigators from the University of Washington (UW) School of Medicine explained that TVUS misses more than four times as many cases of endometrial cancer in Black women as it does in their white counterparts.
TVUS assesses cancer risk by measuring the thickness of the endometrium, but Black women experience more uterine fibroids and non-endometrioid histology type, said the team led by Kemi Doll, M.D., a gynecologic oncologist at UW, putting them at a higher risk for a false-negative result. This puts Black women, who are already vulnerable to the worst endometrial cancer outcomes, at even greater risk.
“Black women had an over 90 percent higher mortality rate after diagnosis of endometrial cancer when compared with white women in the [United States,]” Doll said. “This is a long-standing disparity that we have yet to make meaningful progress to address. Although we have focused before on evaluating access to healthcare, in this study, we sought to evaluate the guidelines themselves.”
Overall, the team said, their findings show that adhering to current clinical guidelines is unacceptable because it leads to under-diagnosis of Black women. Addressing this racial inequality is critical, they added, because the inequity in survival is larger than with cervical, breast, and colon cancers – and it’s rising.
TVUS measurements typically indicate that biopsy is necessary when the endometrium is 4 mm thick of greater. However, the tests that determined that benchmark were conducted only with population-based studies from Scandinavia, Italy, and Hong Kong. Black women were not included.
For their study, the team used a simulated retrospective cohort study that was based on data from the Surveillance, Epidemiology, and End Results (SEER) national cancer registry from 2012 to 2016, as well as the U.S. Census. They constructed a second SEER-based cohort with data from Feb. 2, 2020, to Aug. 31, 2020. All total, they included 367,073 simulated Black and white women with post-menopausal bleeding, including 36,708 with endometrial cancer.
Based on their analysis, the team found that, for endometrium thickness measurements of 4 mm or more, fewer than half of Black women were referred for biopsy. Among those who were, 13.1 percent were diagnosed. With white women, however, the same thickness measurement referred most women for biopsy, and 14.6 percent were diagnosed with endometrial cancer.
More specifically, TVUS with Black women had 47.5 percent sensitivity, a negative predictive value of 92 percent, and an area under the curve (AUC) of 0.57. For white women, the screening produced 87.9 percent sensitivity, a negative predictive value of 98 percent, and an AUC of 0.73. These results indicate a five-fold difference in population-level performance and a two-fold difference at the individual level.
The implication from these findings is important, the team said. Black women are consistently diagnosed with more advanced stages of endometrial cancer, and these results point to likely TVUS failure for this patient group even if they present with symptoms and undergo appropriate diagnostic procedures.
In an accompanying editorial, Eloise Chapman-Davis, M.D., a gynecologic oncologist from Weill Cornell Medicine, and Dineo Khabele, M.D., chair of the department of obstetrics and gynecology at Washington University School of Medicine in St. Louis, commended Doll’s team for their work and said these results should factor into changes to existing TVUS guidelines.
“Taken together, these results suggest current TVUS clinical guidelines fall short in detecting [endometrial cancer] when simulated for Black women,” they said. “These findings may partially explain failures and delays in diagnosis that lead to advanced-stage disease and excess mortality for Black women. New risk-based clinical algorithms should be developed to account for the higher prevalence of non-endometrioid [endometrial cancer] and fibroids among Black women.”
Although real-world studies are needed to confirm the study’s outcome, the team did stress that providers must be aware of and take into consideration that TVUS may potentially miss an endometrial cancer diagnosis in Black patients. If fibroid are present, they should discuss biopsy as a screening option despite its greater invasiveness.
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