Summary: A new study in JAMA Oncology reveals that the common algorithm for detecting endometrial cancer is unreliable for Black women, recommending tissue biopsies over transvaginal ultrasounds due to nearly 10% of cancer cases being undetected by the latter.

Key Takeaways:

  1. Unreliable Detection Algorithm: A new study in JAMA Oncology found that the common algorithm for detecting endometrial cancer is unreliable for Black women, leading to recommendations for tissue biopsies over transvaginal ultrasounds for those with concerning symptoms.
  2. High Risk of Misdiagnosis: Transvaginal ultrasound, which measures endometrial thickness, is less effective for Black women, with nearly 10% of endometrial cancer cases going undetected due to thinner endometrial measurements.
  3. Racial Bias and Ineffectiveness: The study highlights racial bias in ultrasound accuracy, emphasizing that diagnostic protocols need to be adjusted for Black women due to factors like fibroids, body size, and technician skill affecting the visibility of cancers.


A common algorithm for detecting endometrial cancer is unreliable for Black women, according to a new study in JAMA Oncology. The study recommends a tissue biopsy for Black patients with concerning symptoms, instead of relying on transvaginal ultrasound.

Endometrial cancer is the most common gynecological cancer in the U.S. and is rising, especially among Black women, who are often diagnosed at later stages. Symptoms include abnormal vaginal bleeding, pelvic pain, and difficulty urinating, according to the American Cancer Society.

Disparities in Endometrial Cancer Diagnosis

Transvaginal ultrasound, which allows detailed views of pelvic organs, is less effective for Black women. Nearly 10% of patients with endometrial cancer had an endometrial thickness below the common 4-millimeter cut-off.

“This is just not acceptable,” says Kemi Doll, MD, MCSR, lead author and gynecologic oncologist at the University of Washington School of Medicine and the Fred Hutchinson Cancer Center. The test is supposed to be 99% to 100% accurate for ruling out endometrial cancer, but that’s not the experience of Black women, she notes.

“What we found in real-world clinical scenarios is that it’s just not accurate enough to be safely employed as a strategy among Black people. Whereas, a tissue biopsy is conclusive,” Doll adds.

Transvaginal ultrasound involves inserting a probe into the vagina to capture images of the uterus, ovaries, fallopian tubes, and other structures. It measures endometrial thickness, which can indicate cancer. A normal thickness is usually less than 4 millimeters in postmenopausal women. A thicker endometrium can suggest abnormal cells or tumors, leading to a biopsy. If the thickness is under 4 millimeters, a biopsy may not be performed, assuming the patient is cancer-free.

That protocol can be deadly for Black patients. “We found that 9.5% of the cancers in Black women were detected below the threshold of 4 millimeters, and 11.5% of the cancers would have been missed at 5 millimeters,” Doll says.

Flaws in Cancer Detection for Black Women

Diagnostic protocols were established for the general population, but for Black women, factors like decreased visibility of cancers, increased fibroids, larger body size, and technician skill affect accuracy.

“You might have a cancerous lesion in one area, but not another, and if you don’t look in that specific area, you might assume the patient is cancer-free,” Doll says. For high-risk groups like Black women with symptoms of endometrial cancer, Doll emphasized, “you need to do more.” A tissue sample should be the first test, not an optional follow-up.

This study supports previous findings of racial bias in ultrasound accuracy for endometrial cancer. A 2019 study in the Journal of Clinical Oncology found Black women had a higher risk of false-negative ultrasounds, meaning their endometrial thickness was measured as normal despite having cancer.

Another study led by Doll in 2020 found the algorithm underperforms in Black women due to fibroids and high-risk cancers causing less thickening of the endometrium.

Uterine Cancer Outcomes in Black Women

The American Cancer Society notes that nearly 70,000 women will be diagnosed with uterine cancer this year, and more than 13,000 will die from it.

The new study involved a retrospective analysis of electronic health record data and administrative data from Black individuals who underwent hysterectomies at 10 hospitals in one health system. The analysis, performed in 2023, included the University of North Carolina at Chapel Hill, the University of Michigan, and Duke University.