Using transvaginal ultrasound to measure endometrial thickness to determine if symptomatic women need biopsy missed almost five times more cases of endometrial cancer among Black women than white women, according to research published July 15 in JAMA Oncology.
Researchers led by Dr. Kemi Doll from the University of Washington in Seattle found that this method of diagnostic testing resulted in lower sensitivity and negative predictive value among Black women compared with white women.
"In this study, the results suggest that the current option of transvaginal ultrasonography to determine the appropriateness of endometrial biopsy is neither sufficiently accurate nor racially equitable," the study authors wrote.
Endometrial cancer is the fourth most common cancer in the U.S. with an estimated 61,880 newly diagnosed cases and 12,160 cancer deaths in 2019, according to data published by the American Cancer Society. Black women with this cancer have a 90% higher five-year mortality rate after diagnosis compared with white women.
Postmenopausal bleeding is a symptom found in about 90% of women diagnosed with endometrial cancer. Current recommendations say transvaginal ultrasound is the only noninvasive strategy when determining whether patients who present with such bleeding need biopsy. It is used to measure endometrial thickness and must meet a certain threshold (4 mm) to prompt an invasive test.
In the current study, the team wanted to compare the performance of using recommended transvaginal ultrasonography endometrial thickness thresholds as a screening method for biopsy by race in a simulated cohort of symptomatic women.
The study was based on data from the Surveillance, Epidemiology, and End Results (SEER) national cancer registry from 2012 to 2016, the U.S. census, and published estimates of endometrial thickness distribution, fibroid prevalence, and diagnostic test characteristics.
The researchers looked at data from 367,073 simulated patients, including 44,611 Black women and 322,462 white women with postmenopausal bleeding. Out of the total cohort population, 36,708 had endometrial cancer. For Black women, the 4-mm threshold prompted biopsy in only 47.5% of cases, versus 87.9% of white women.
| Accuracy of transvaginal ultrasonography for endometrial cancer (4 mm), by race | ||
| Black women | White women | |
| Sensitivity | 47.5% | 87.9% |
| Endometrial cancer cases after biopsy referral | 13.1% | 14.6% |
| Positive predictive value | 13.1% | 14.6% |
| Negative predictive value | 91.7% | 97% |
| Area under the curve | 0.57 | 0.73 |
The authors noted the same variations held for the 3-mm or more and 5-mm or more endometrial thickness thresholds. Sensitivity, positive predictive value, and area under the curve were "consistently lower" for Black women than white women.
The authors suggested that the lower performance in Black women of using endometrial thickness in determining whether to send women to biopsy could result in women with cancer presenting at a later stage. They also suggested that ultrasound's lower performance might be due to higher rates of fibroids and nonendometrioid endometrial cancer in Black women.
While the study's results come from a simulated cohort, they have important implications, according to an accompanying editorial written by Dr. Eloise Chapman-Davis from Weill Cornell Medicine in New York and Dr. Dineo Khabele from the Washington University School of Medicine in St. Louis.
"The investigators found that the most basic clinical guideline -- recognition and intervention for the most common presenting symptom of endometrial cancer -- is missed in Black women," they wrote.
"An ancient clinical practice is to listen to the patient," they added. "When will we listen to Black women?"
