Women in the United States have experienced a steep rise in rates of aggressive uterine cancer since 2000, an upward trend that has been particularly steep for minority women, according to a new study.
Particularly troubling, the study found that non-Hispanic black women are not only more likely to develop such cancers but are more likely to die from them.
Uterine cancer is the second deadliest form of gynecological cancer in the country, resulting in more than 63,000 new diagnoses and killing more than 11,000 women in 2018.
The researchers from the National Cancer Institute examined a large database representing 28 percent of the U.S. population, focusing on women ages 30-70. They estimated rates of an aggressive type of uterine cancer — called non-endometrioid cancer because it can begin outside the uterine lining (endometrium) — to have risen about 3 percent each year from 2000 to 2015 across all racial and ethnic groups.
However, the incidence of non-endometrioid uterine cancer was greatest among non-Hispanic black women over that same period. This aggressive form of uterine cancer was found in 26 out of 100,000 black women (non-Hispanic), compared with 11 out of 100,000 white women (non-Hispanic), 10 out of 100,000 Hispanic women, and 7.5 out of 100,000 Asian/Pacific Islander women (non-Hispanic). Further, even though Hispanic and Asian women have lower incidence of non-endometrioid uterine cancer overall, their rates are increasing more rapidly than other groups of women.
Notably, this study accounted for the prevalence of hysterectomies, a surgical removal of the uterus that eliminates the risk of uterine cancer. Many prior studies that have looked at large databases did not properly eliminate women who have undergone the procedure, a population that varies significantly depending on age, race, ethnicity, geography, and other factors.
“Endometrioid carcinomas are more likely to be diagnosed at an early stage, with good overall survival; they are described as estrogen dependent and are more strongly associated with obesity,” the authors wrote. “In contrast, patients with non-endometrioid carcinomas have worse survival, and risk has been less strongly associated with estrogen-related risk factors and obesity. Thus, the observed increases in non-endometrioid cancer incidence, combined with more stable rates of endometrioid cancers, challenge the prevailing hypothesis that the obesity epidemic and changing prevalence of hormonal risk factors are major contributors to rising uterine cancer incidence.”
The authors called for the need to study the issue further to identify risk factors and exposures more closely linked with non-endometrioid cancers and to better understand the clear racial disparities.
“This study highlights a steadily expanding body of evidence demanding that we further explore differences between and among populations of women and men,” said Dr. Carolyn M. Mazure, Director of Women’s Health Research at Yale. “We must learn what is behind these disparities in order to create safe and effective prevention and treatment strategies that target the different ways in which diseases like this develop in different individuals based on their sex, gender, race, and ethnicity.”