African-American and Hispanic women were more likely to be diagnosed with late-stage breast cancer than non-Hispanic Whites and were at higher risk of not receiving recommended treatment across breast cancer subtypes, according to a new study led by a PhD student in epidemiology at the University of Washington School of Public Health.

The study, published in Cancer Epidemiology, Biomarkers and Prevention, is believed to be the largest yet to look at breast cancer treatment in the U.S.  Researchers examined data from more than 102,000 women in the Surveillance, Epidemiology, and End Results program of the National Cancer Institute.

“We saw a consistent pattern of late diagnosis and not receiving recommended treatment for African-American women across all breast cancer subtypes,” first author Lu Chen, a University of Washington student based at the Fred Hutch research center in Seattle, told the Huffington Post. Those subtypes include the more common luminal tumors and less common but more aggressive HER2 overexpressing and triple negative tumors, Chen said.

African-American and Hispanic women were 30 percent to 60 percent more likely to be diagnosed with stage II-IV breast cancer than Whites, the study found. In addition, African-American women had 40 percent to 70 percent higher risks of stage IV breast cancer across all four subtypes.

African-American and non-Hispanic Whites were less likely to receive the recommended treatments across every subtype of breast cancer. American Indian/Alaska Native women had a nearly four-fold higher risk of stage IV triple-negative breast cancer.

Ms. Chen conducted the research with Christopher Li, a research professor of epidemiology at the University of Washington and a member of the Fred Hutch Public Health Sciences Division. The authors said the disparities are likely driven by socio-economic factors and access to care.

“Continued efforts, especially targeted, culturally appropriate interventions, to address these disparities across different subtypes of breast cancer have the potential to reduce these long-standing disparities and hopefully close the existing survival gaps,” the authors conclude.