Non-Hispanic black women with endometrial cancer had worse outcomes than women in other racial/ethnic groups diagnosed with the same subtype of endometrial cancer and at the same stage of disease. This study was published in Cancer Epidemiology, Biomarkers & Prevention (2015; doi:10.1158/1055-9965.EPI-15-0316).
The lead author, Michele L. Cote, PhD, an associate professor of oncology at the Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine in Detroit, Michigan, explained that endometrial cancer is the most commonly diagnosed gynecologic cancer in the United States and that incidence rates have been rising for many years. For this study, she and her colleagues set out to investigate whether the increasing incidence and mortality from endometrial cancer are equally distributed by race/ethnicity and endometrial cancer subtype, she said.
Cote and colleagues analyzed endometrial cancer incidence and mortality data from the Surveillance, Epidemiology, End Results (SEER) database, including only the 120,513 cases diagnosed from 2000 to 2011.
Over the 12 years studied, endometrial cancer incidence rates increased among all racial and ethnic groups, with rates increasing fastest, at 2.5% per year, among non-Hispanic black women and Asian women. Non-Hispanic black women had higher rates of all the aggressive endometrial cancer subtypes than non-Hispanic white, Asian, and Hispanic women.
Mortality rates for the aggressive endometrial cancer subtypes were more than 1.5-fold higher among non-Hispanic black women compared with non-Hispanic white women, while mortality rates for these subtypes were similar or lower among Asian and Hispanic women compared with non-Hispanic white women.
Analysis of overall five-year survival rates showed that non-Hispanic black women had poorer survival at every stage of diagnosis, regardless of endometrial cancer subtype, compared with non-Hispanic white women, while five-year survival rates were similar or higher among Asian and Hispanic women compared with non-Hispanic white women.
“The most significant finding was that non-Hispanic black women had poorer outcomes compared with non-Hispanic white women diagnosed with the same subtype of endometrial cancer and at the same stage of disease, while Hispanic and Asian women had similar or better outcomes compared with their non-Hispanic white counterparts,” said Cote in an interview.
“Prior studies have suggested that disparities in outcomes from endometrial cancer might be explained by differences in tumor subtype or stage at diagnosis, but our data suggest that disparities persist even when these factors are controlled for.
“It was somewhat surprising that the endometrial cancer survival disparity we identified was limited to non-Hispanic black women because many of the challenges previously linked to worse outcomes, including low socioeconomic status and high rates of obesity and diabetes, are also experienced by Hispanic women, but that population did not have poor outcomes,” she added.
Cote explained that this puzzle has led to their interest in investigating whether molecular differences exist in endometrial tumors of the same subtype from women of different races or ethnicities diagnosed at the same stage of disease.
Cote stated that a limitation of the study is that the data analyzed were from the SEER database, which meant the researchers did not have tumor samples and were, therefore, unable to perform a review of the tumor subtype to ensure they had been classified correctly. In addition, SEER does not collect information on other factors that may be associated with incidence and survival, thus potential causes for the disparities identified in this study cannot be further examined.