ASCO Breast: Worse Outcome in Blacks Linked to Higher Rate of ER-Negative Cancers

SAN FRANCISCO, Sept 10-Biology, rather than access, income, or education, is the major driver of the well-recognized racial differences in breast cancer outcome, researchers reported here.

African American women are more likely to have estrogen receptor–negative breast cancer, a decided disadvantage in an era when most treatment breakthroughs have occurred in the field of hormone-positive breast cancers, said M. Catherine Lee, MD, of the University of Michigan Health Systems in Ann Arbor.

Hormone-negative tumors, she told attendees at the American Society of Clinical Oncology’s Breast Cancer Symposium, are not only more aggressive but also less responsive to treatment. And, there are fewer treatment options for these cancers.

Dr Lee and colleagues analyzed 170,079 breast cancer cases diagnosed in 1998 that had been included in the National Cancer Data Base, a registry maintained by the American College of Surgeons. Roughly 17,000 of those cases occurred in African American women.

At every age and every stage, estrogen receptor–negative cancers were more common among African American women than among white women, Dr Lee said.

In addition, black women were more likely to receive a diagnosis at a younger age, but later stage than white women.

Among the findings:

• The mean age at diagnosis was 57 for African American women compared with 62 for white women (P<.001).
• At diagnosis, 22% of black women were younger than 45 versus 13% of white women (P<.001).
• At diagnosis, 29% of African American women had stage I disease compared with 42% of white women, and the median size of tumors was 2 cm versus 1.5 cm, respectively.
• More than 52% of African American women younger than 45 had ER-negative tumors versus 35.2% of white women (P<.01) and that statistically significant difference continued through the ninth decade of life.
• More than 30% of stage I cancers and 45.5% of stage IV cancers in African American women were ER-negative versus 16.9% and 30.6%, respectively, in white women (P<.01).

Julie Gralow, MD, of the University of Washington School of Medicine said the findings “bring to the forefront the basic biology of breast cancer.”

Confirming a higher rate of ER-negative breast cancer at “any stage of diagnosis is important because it demonstrates that this is not just an issue of access to care and access to treatment,” she said.

Dr Gralow, who moderated an ASCO press conference where the results were discussed, was not involved in the study.

Dr Lee said the rate of ER-negative breast cancers in African American women was likely to “affect accrual patterns in future clinical trials of endocrine-sensitive treatments.”