A new study found that a common screening tool for endometrial cancer frequently under-identifies signs of cancer in Black women. This study was published in JAMA Oncology.
Endometrial cancer is the fourth most common cancer type in the United States, with more than 61,000 new cases in 2019.
“Black women have an over 90% higher mortality rate after diagnosis of endometrial cancer when compared with White women in the U.S.,” said lead researcher Kemi Doll, MD, gynecologic oncologist at the University of Washington School of Medicine, via a press release. “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.”
Dr. Doll and colleagues utilized a simulated cohort to assess the predictive accuracy of transvaginal ultrasound (TVUS) for identifying endometrial cancer, as well as racial disparities in those screening thresholds. TVUS is used to measure endometrial thickness (ET), with thresholds that would trigger a referral for biopsy for cancer detection. According to the authors, this testing strategy was developed using large population-based studies from Scandinavia, Italy and Hong Kong, and Black women were not included in these studies.
Different Results for Black and White Patients
To construct the sample, the team used data from the Surveillance, Epidemiology, and End Results (SEER) national cancer registry between 2012 and 2016 as well as the U.S. census. The simulated cohort included 367,073 patients, including 36,708 confirmed cases of endometrial cancer, and was made up of Black and white patients.
According to the data, the current recommendation of a ≥4 mm ET threshold to prompt biopsy for cancer missed more than half of endometrial cancer cases among Black women, or a sensitivity of 47.5% (95% confidence interval [CI], 46.0–49.0). Of Black women whose TVUS results triggered biopsy referral, 13.1% led to a confirmed endometrial cancer case, for a positive predictive value of 13.1% (95% CI, 12.5–13.6%). The area under the curve (AUC) for the ≥4 mm ET threshold was 0.57 (95% CI, 0.56–0.57).
Among white patients, the ≥4 mm ET threshold for prompting biopsy achieved a sensitivity of 87.9% (95% CI, 87.6–88.3). Fourteen percent of white women referred for biopsy had endometrial cancer (positive predictive value, 14.6%; 95% CI, 14.4–14.7). The AUC was 0.73 (95% CI, 0.73–0.74). The ≥3 mm threshold and the ≥5 mm thresholds also showed consistently lower sensitivity, positive predictive value, and AUC for Black women compared with white women.
“This puts Black women at a higher risk of false-negative results,” said Dr. Doll. “That is unacceptable in a group that is already the most vulnerable to the worst outcomes of endometrial cancer.”
In conclusion, the authors wrote, “The findings of this simulated cohort study suggest that use of ET as measured by TVUS to determine the need for endometrial cancer diagnostic testing in symptomatic women may exacerbate racial disparities in endometrial cancer stage at diagnosis. In simulated data, TVUS ET screening missed almost 5 times more cases of endometrial cancer among Black women versus white women, owing to the greater prevalence of fibroids and nonendometrioid histologic type in Black women.”
Dr. Doll noted, “Not all endometrial cancer increase the lining thickness. In addition, non-cancerous fibroids can make the lining harder to measure.” She says that the next step is to confirm these results in a real-world study.