Black women accounted for just under 10 percent of the 208,587 uterine cancer cases diagnosed in the United States between 2000 and 2017, but they made up nearly 18 percent of the nearly 16,797 uterine cancer deaths during that period, the study by Dr. Clarke.

The death rate from uterine cancer for black women is 31.4 per 100,000 women age 40 and older, compared with 15.2 per 100,000 for white women in the same age group, Dr. Clarke. (Comparable death rates for Asian-American women were nine per 100,000, and 12.3 per 100,000 for Hispanic Americans.)

That makes uterine cancer an outlier, as progress has been made over the past two decades in narrowing the racial gap in death rates from most cancers. Another report from the National Cancer Institute, published in JAMA Oncology in May, found that cancer death rates among black Americans have generally declined steadily between 1999 and 2019, although they are still higher than those of other racial and ethnic groups. .

The reasons for the increase in uterine cancers are not well understood. The most common form, endometrioid cancer, is associated with exposure to estrogen, which is higher when obesity is present, and obesity rates have risen in the United States.

But non-endometrioid cancer has also increased in prevalence, and it’s not linked to being overweight. From the study of Dr. Clarke found that black women are more likely to have this aggressive form of uterine cancer. They are less likely to be diagnosed early in the course of the disease and their survival rates are worse regardless of when they are diagnosed and what subtype of the cancer they have.

“At every stage of diagnosis, there are different outcomes,” says Dr. Karen Knudsen, chief executive of the American Cancer Society. “Are they getting access to the same quality of cancer care?” She calls for more research into the factors driving the trends.