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A link between estrogen receptor–negative (ER-negative) and triple-negative breast cancer and African ancestry has been reported again in a new study published online July 22 in Cancer. Researchers from the University of Michigan Comprehensive Cancer Center in Ann Arbor report that in their cohort, 82% of African women and 26% of American women of African ancestry had triple-negative disease. This was compared with 16% of white American patients with breast cancer.

As previously reported by Medscape Medical News, black women tend to be diagnosed at a younger age, present with a more advanced stage of disease at diagnosis, and have a higher risk for recurrence. They are also more likely to present with the triple-negative phenotype (negative for ER, progesterone receptor [PR], and human epidermal growth factor receptor 2 [HER2]), and are more likely to be ER-negative, which makes these women ineligible for hormone therapy.

Although the overall incidence of breast cancer among American black women is lower than in white women, breast cancer–related mortality is higher. However, even though multiple factors play a role in this disparity, studies have also shown that there may be biologic differences involved.

"While there are socioeconomic, cultural beliefs, and lifestyle factors involved, we believe that molecular differences also contribute to the more aggressive clinical features of breast tumors seen in these women," said Lori Field, PhD, the lead author of a study on genetic differences between black and white patients with breast cancer that was presented at the American Association for Cancer Research 2008 Annual Meeting. Dr. Field was with the Windber Research Institute, in Pennsylvania, when she presented her data.

Another recent study reported that triple-negative disease is 3-fold more common in black women compared with other races, regardless of age or body mass index. (Breast Cancer Res. 2009;11:R18).

Highest Prevalence of ER-Negative and Triple-Negative Disease

"A primary message of this work is that initiation of mammography screening at age 40 is particularly important for African-American women because of their increased risk for early-onset disease and for disease that is biologically more aggressive," said lead author Lisa A. Newman, MD, MPH, director of the Breast Care Center at the University of Michigan.

"Early detection of triple-negative breast tumors is extremely important," she told Medscape Medical News. "I personally advocate for mammography screening beginning at age 40 for white American women as well, in accord with American Cancer Society and American College of Surgeons recommendations."

In the latest study, Dr. Newman and colleagues compared disease patterns and selected clinicopathologic features among white and black American patients with breast cancer and African women with breast cancer who were treated at the Komfo Anokye Teaching Hospital in Kumasi, Ghana.

The study cohort included 1008 white American women, 581 black American women, and 75 Ghanaians, all of whom were diagnosed with invasive breast cancer. The mean age at the time of the diagnosis for Ghanaian women was 48 years, which was considerably lower than the median 60.7 years for black American women and 62.4 years for white American women (P = .0019).

The authors noted that the percentage of grade 3 lesions was also higher for the Ghanaian patients, as was the tumor size. Approximately three quarters (76%) of the Ghanaian patients were also diagnosed with ER-negative tumors compared with 36% for black American women and 22% for white American women. Ghanaian women also had the highest prevalence of triple-negative breast cancers observed in this group.

Source: MedScape