A cohort study has found increases in mortality rates among women with non-endometrioid uterine carcinoma, despite incident rates that have stabilized. After correction with hysterectomy, mortality risk was about doubled for Black women, compared with White women, and these results could not be explained by differences in cancer subtype or cancer stage at diagnosis. Non-endometroid uterine carcinoma represents 15%-20% of uterine cancers diagnosed and carries a worse prognosis.
“We do not know why non-endometrioid subtypes are disproportionately increasing among all women, nor do we understand why they are so much more common among non-Hispanic Black women. We need more research to identify risk factors and exposures more specifically associated with non-endometrioid cancers to better understand the strong increases in this subtype among all women and the particularly high rates and recent increases in non-Hispanic black women,” said lead author Megan Clarke, PhD, MHS, the study’s lead author and a cancer epidemiologist with the National Cancer Institute.
The study was published online in JAMA Oncology.
“Physicians should be aware that both incidence and mortality rates of non-endometrioid cancers are on the rise. Because these subtypes are rarer than endometrioid uterine cancers, physicians may be less familiar with diagnosing and treating these aggressive types of cancers. Increasing awareness among clinicians and patients regarding the signs and symptoms of uterine cancer (such as postmenopausal bleeding) and the differences in histologic subtypes among racial and ethnic groups may promote earlier diagnosis and timely referral to appropriate treatment,” Dr. Clarke said.
Previous studies based on death certificates found increased mortality, especially in Black women, but they were limited by an inability to link mortality to tumor characteristics. To address this, the researchers linked mortality data to records of 208,587 women diagnosed with uterine cancer between 2000 and 2017, drawn from the U.S. Surveillance, Epidemiology, and End Results (SEER) Program.
Black women represented 9.7% of cases, but they suffered 17.7% of uterine cancer deaths. Overall, mortality from uterine corpus cancer increased by 1.8% per year (95% confidence interval, 1.5%-2.9%). Non-endometroid cancers increased at 2.7% per year (95% CI, 1.8%-3.6%), and this was higher in Asian (3.4%; 95% CI, 0.3%-6.6%), Black (3.5%; 95% CI, 2.2%-4.9%), Hispanic (6.7%; 95% CI, 1.9%-11.8%), and White women (1.5%; 95% CI, 0.6%-2.4%).
Mortality increased 1.8% per year overall for uterine cancer and 2.7% per year for non-endometrioid uterine cancer. There was no increase in mortality seen in endometrioid cancers.
“The concerning rise in deaths from non-endometrioid cancers warrants clinical attention. Our findings suggest that there may be several factors contributing to racial disparities in uterine cancer mortality. Higher mortality rates among non-Hispanic Black women are partly attributable to higher incidence of tumors with aggressive subtypes and advanced stages. However, non-Hispanic Black women in our study who were diagnosed with less aggressive subtypes and early-stage disease also had the highest mortality rates,” said Dr. Clarke.
That suggests that inequities of treatment and high-quality care may be at least partly to blame, since those factors are known to contribute to differences in uterine cancer outcomes. “Other factors including comorbidities, health care facility characteristics, treatment preferences and adherence, patient and provider communication, provider bias, discrimination and structural racism, and potential biologic differences in response to treatment need to be better understood in terms of how they influence racial disparities,” Dr. Clarke said.
Dr. Clarke reported no relevant disclosures.