A recent study confirmed disparities in breast cancer diagnosis, treatment, and survival among American women from a wide-range of racial and ethnic backgrounds.

According to Christopher Li, MD, PhD, at the Fred Hutchinson Cancer Research Center in Seattle, "There is reason to believe that there would be differences in breast cancer outcomes based on diverse cultural practices, dietary habits, and possibly genetics. But, socioeconomic factors are likely to play the most important role."

Li said while biological differences could be a contributing factor, he suspects that lack of access to health care is the largest factor behind the increased mortality (death) rates for African Americans, Native Americans, and Hispanics.

Li based his comments on findings from the largest, most comprehensive study of its kind to evaluate the relationship between race and ethnicity, and breast cancer stage, treatment, and survival. He and his colleagues reported results in the Archives of Internal Medicine (Vol. 163: 49-56).

The study evaluated data from 125,000 women representing all major racial and ethnic populations and subpopulations in the US. Data for the study came from 11 tumor registries that are a part of the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) program.

The researchers analyzed medical data from 124,934 women from Seattle, San Francisco/Oakland, Los Angeles, San Jose, Atlanta, Detroit, Connecticut, Hawaii, Iowa, New Mexico, and Utah. All women were diagnosed with breast cancer between 1992 and 1998.

"We were able to look at eight subgroups of Asian/Pacific Islanders and four subgroups of Hispanic whites in addition to non-Hispanic whites, African Americans, and Native Americans," Li said.

Among Asian/Pacific Islanders and Hispanic whites, significant differences in diagnosis, treatment, and outcome were found among women of various racial and ethnic subcategories, including Japanese, Filipino, Indian/Pakistani, Mexican, South and Central American, and Puerto Rican descent.

Regarding stage of disease, the study found:

African Americans, Native Americans, and Hispanic whites were more likely to be diagnosed with tumors that were more advanced than were non-Hispanic whites and Asian/Pacific Islanders.

Japanese women were 30% less likely to be diagnosed with late-stage breast cancer while women of Filipino, Hawaiian, Indian/Pakistani, Mexican, South and Central American, and Puerto Rican descent were 20% to 260% more likely to be diagnosed with late-stage breast cancer when compared to non-Hispanic white women.

When looking at treatment, the study found:

Puerto Rican women fared the worst, as they were 50% more likely to receive substandard, inappropriate treatment for breast cancer.

African American women were 40% more likely to undergo initial treatment that was below national standards as compared to non-Hispanic whites.

And finally, the study showed disparities in survival:

Japanese and Chinese women had better survival rates after breast cancer while Hawaiian and Mexican women had 30% poorer survival rates when compared to non-Hispanic whites.

African American, Native American, and Hispanic white women faced a 10% to 70% greater risk of dying after a breast cancer diagnosis as compared to non-Hispanic whites.

Li said, "One of the most disturbing trends identified by our research is that we have known since the 1970s that certain racial/ethnic groups, such as African Americans, have poorer breast cancer outcomes. Despite having several decades to improve this situation, it remains an important problem."