FRIDAY, May 16, 2014 (HealthDay News) -- Black women are nearly twice as likely as white women to be diagnosed with a hard-to-treat breast cancer known as triple-negative breast cancer, a new study says.
That dramatic difference was found no matter what their socioeconomic level was, the researchers added.
"The excess odds of triple-negative breast cancer in blacks compared to whites were remarkably similar, about 80 percent higher, in each socioeconomic group," study author Dr. Helmneh Sineshaw said in a news release from American Cancer Society.
"That consistent increase suggests factors other than differences in socioeconomic status play a strong role in the excess odds seen in black women. Further studies are needed to identify those factors," added Sineshaw, who is a senior epidemiologist and health services researcher at the American Cancer Society.
Triple-negative breast cancer is a type of breast cancer that doesn't have receptors for the hormones estrogen or progesterone. This type of cancer also doesn't have too much of another hormone -- called HER2 -- on the surface of the cancer cell, according to the American Cancer Society.
Triple-negative breast cancers tend to grow and spread more quickly than other types of breast cancers. And, because many breast cancer treatments target hormones, this type of cancer has fewer treatment options.
Previous research has found that black and Hispanic women were more likely than whites to develop triple-negative breast cancer, and some of the studies suggested that this could be due to differences in wealth.
In this new study, researchers analyzed data from more than 260,000 breast cancer cases, and found that poor women had higher rates of triple-negative breast cancer.
However, when the researchers adjusted the data to account for factors such as income, black women were still 1.84 times more likely to be diagnosed with triple-negative breast cancer than white women. The findings were recently published online in the journal Breast Cancer Research and Treatment.
The researchers also found that Asian/Pacific Islanders were more likely than whites to develop a type of breast cancer known as HER2-overexpressing breast cancer, and that this difference was also seen at all socioeconomic levels.
The U.S. National Library of Medicine has more about breast cancer.