All 13,585 women in the study were insured by the same health system, and the findings released on August 14, 2026 show Black women under 65 died of uterine cancer at more than twice the rate of White women.
The usual explanation for that gap is coverage. Younger women are less likely to be insured before Medicare begins at 65, so the reasoning goes, and they reach a doctor later. This study removed that variable. Every patient in it was a Kaiser Permanente member in Northern or Southern California, diagnosed between 2005 and 2022, with the same access to the same care. The gap did not close. It was 43 percent wider among the patients under 65.
“Overall, our findings refute the notion that insurance explains the bigger survival gap in young patients,” said Dr. Betty Suh-Burgmann, the gynecologic oncologist who led the work.
What the researchers found instead was a difference in the tumors. Older Black women were about twice as likely as older White women to be diagnosed with aggressive type tumors. Younger Black women were about three times as likely.
Why that is, nobody has established. “Nobody knows the answer,” Suh-Burgmann said, though she named environmental exposures such as pesticides as a possibility.
The work was published in JAMA Network Open. Its senior author, Dr. Julie Schmittdiel, said it shows the need for more research to identify why younger Black women are developing these more aggressive tumors and to determine how to tailor care to them.
