Stubborn Form of Breast Cancer Linked to Age, Race, Ethnicity

An aggressive and difficult-to-treat form of breast cancer appears to be more common in young African-American and Hispanic women, according to the results of a new study.

The class of disease is called "triple negative" breast cancer, which means the tumors lack receptors for the hormones estrogen (ER-negative) and progesterone (PR-negative), and for the protein HER2. This makes them resistant to several powerful cancer-fighting drugs like tamoxifen, aromatase inhibitors, and Herceptin.

The finding points to the need for continued research on the breast cancer survival gap between African-American, Hispanic and white women, says the study's lead author, Katrina Bauer, MS, of the California Cancer Registry. This survival gap persists even with equal treatment, studies show. Perhaps the breast cancer is biologically different depending on race or ethnicity.

"Although African American women and Hispanic women have a lower incidence of breast cancer, they are more likely to develop this aggressive form of breast cancer," Bauer says.

Her study appears in Cancer, a journal of the American Cancer Society.

Her research team examined records on 6,370 women diagnosed with triple-negative breast cancer and 44,704 women with other forms of the disease from 1999 to 2003. They found 63% of women with triple-negative tumors were diagnosed before age 60, whereas less than 50% of women with other forms of breast cancer were diagnosed in that age range.

This form of cancer was more common in African-American and Hispanic women. About 25% of African Americans had triple-negative breast cancer, while 17% of Hispanics, 12% of Asian/Pacific Islanders, and 11% of whites did. Women with this type of cancer were more likely to have larger, more advanced tumors at diagnosis.

Triple-negative cancer was deadlier than other types of breast cancer. Only 77% of women survived 5 years after a triple-negative diagnosis, compared with 93% of women with other forms of the disease.

Of course, surgery and chemotherapy are standard treatment options for most forms of breast cancer, including triple-negative cancer. But unlike hormone-positive and HER2-positive breast cancers, few drugs exist to help battle the recurrence of triple-negative cancer. However, researchers are working to find targeted drugs that might help women with this form of breast cancer.

The study authors say more research is needed to fully understand the role of race, ethnicity, age, and socioeconomic factors in triple-negative breast cancer diagnosis. Also, tumor receptor status will continue to play an important role in how doctors and patients decide their treatment options, the authors say.