Endometrial cancer rates have increased statewide over two decades, with the most dramatic rise taking place in a geographic area that includes Bexar County, according to a new study from UT Health San Antonio.

Endometrial cancer starts in the lining of the uterus known as the endometrium. It’s the most common gynecological cancer in the U.S., with an estimated 69,120 new cases and 13,860 deaths in 2025, according to the American Cancer Society.

The study, led by UT Health gynecological oncologist Dr. Edward Kost, was the first to examine geographic differences in endometrial cancer rates in Texas, Kost said. The researchers looked at endometrial cancer diagnoses in women aged 20 to 79 years old using data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program, from 2000-2019.

Eight geographic areas were examined, and one stood out: the “Upper-South” region, which stretches from the coast to the border near Del Rio and includes the San Antonio metro area.

Incidence rates for endometrial cancer in this region were roughly 21% higher than the statewide average, at 53.8 cases per 100,000 women in the 2010-2019 period. That’s compared to a statewide average of 44.5 cases per 100,000 women.

The Upper-South region also had the most dramatic increase in incidence rates from 2000-2009 to 2010-2019, at 26%. The southernmost region, which includes Corpus Christi and the Lower Rio Grande Valley, also saw a significant increase of 23% over that period.

“I was very surprised that we really saw such an obvious increase in incidence in the Upper-South region,” Kost said.

Kost was also surprised by the high incidence of endometrial cancer in young Hispanic women in the Upper-South region. 

Most cases of endometrial cancer are diagnosed in women over 50. But cases of early-onset endometrial cancer have been increasing nationwide. In Texas’ Upper-South region, the early-onset endometrial cancer rate in Hispanic women was 17.2 cases per 100,000, much higher than the statewide average of 12.4 cases in Hispanic women under 50.

Although county-level data isn’t available in the study, a 2013 finding at San Antonio’s University Hospital was the starting point for Kost’s study, he said. 

“We knew from some preliminary research that there was a higher incidence of endometrial cancer in Bexar County,” Kost said. “That was from research we had done looking at a University Hospital database.”

That data is not yet publicly available, but it showed much higher rates of endometrial cancer in women under the age of 50 receiving care at University Hospital in the South Texas Medical Center, Kost said. That data set also tied obesity, a major risk factor for endometrial cancer, with the higher rates.

Although survival rates have been decreasing nationwide — driven in part by more cases of rarer and more aggressive subtypes of endometrial cancer — survival rates remained relatively stable across Texas between the 2000s and 2010s.

The study also looked at how socioeconomic factors and demographics influenced incidence rates and survival. Endometrial cancer rates tend to be higher in areas with lower poverty, higher education attainment and higher socioeconomic status, both in Texas and the U.S. as a whole.

“It’s a little bit of a paradox,” Kost said. “You would expect that people who live in areas where you have unfavorable socioeconomic factors and social determinants of health, that you’d have an increased amount of cancer.”

Kost said that one possible explanation is that women who live in poorer areas are simply not as likely to be diagnosed. The symptoms for endometrial cancer — the primary one being abnormal vaginal bleeding — can sometimes be dismissed. And barriers to access to care may come into play.

“It actually takes infrastructure to diagnose cancer,” Kost said. “Not all women know that that’s a risk factor. So you have to have some level of education, and you have to have access to medical care.”

Five-year relative survival rates, however, were lower in poorer areas. There were also racial disparities: Non-Hispanic Black women had significantly lower survival rates at 67%, compared to Hispanic women at 80% and non-Hispanic white women at 87%.

The primary treatment for endometrial cancer is a hysterectomy, but hormone therapy is another option for younger patients in the early stages of the disease who want to preserve fertility. 

Kost said that the paper didn’t set out to understand the why behind the trends researchers observed. But he said that South Texas is home to higher obesity and Type 2 diabetes rates, which are risk factors for the disease.

“One of the things we see in South Texas and the Bexar County area is a higher-than-usual incidence of obesity in children and young adults, which I think is probably one of the biggest risk factors for the development of endometrial cancer in patients under the age of 50,” Kost said. 

But, he added, “We don’t have all the answers.”