Younger black women who get breast cancer are far more likely than other
afflicted women to have a particularly aggressive and lethal form of the
disease, a study found.
Graphic looks at
breast cancer incidence and death rate for women.
[AP] |
The findings suggest that biology may help explain why breast cancer is
deadlier in black women younger than 55 than it is in white women in the same
age group. Other studies have blamed inadequate screening rates.
Since 1990, the average annual breast cancer death rate for younger black
women in the United States has been 15.4 deaths per 100,000 population, versus
9.3 per 100,000 for younger white women.
"It's been long known that breast cancer in African American women is a far
less common disease than in white women. But when it occurs, it seems to be more
aggressive and harder to treat," said study co-author Dr. Lisa Carey of the
University of North Carolina's Lineberger Comprehensive Cancer Center.
In the study in Wednesday's Journal of the American Medical Association,
researchers identified cancer types by looking for certain proteins in tumor
tissue taken from 496 women in the Carolina Breast Cancer Study. The women had
been diagnosed between 1993 and 1996.
A quick-spreading form of breast cancer called the basal-like subtype
appeared in 39 percent of premenopausal black breast cancer patients. It
accounted for 14 percent of breast cancer cases in older black women, and 16
percent of those in non-black women of any age.
Genetic profiling of cancer subtypes has led to a new generation of targeted
drugs that have shown startling success. But for the basal-like subtype, no
targeted therapies yet exist and doctors must use more conventional
chemotherapy.
The research may lead to a better understanding of what causes the aggressive
subtype of breast cancer, said Dr. Eric Winer, director of the breast oncology
center at Dana-Farber Cancer Institute in Boston. He was not involved in the
study.
He said it is unclear whether this subtype is occurring because of an
inherited predisposition or because of something in the environment that black
women are more likely to be exposed to. He added that disparities in access to
treatment still probably account for much of the higher mortality rate among
young black women.
In the study, death rates remained higher for younger black women even when
the basal-like subtype cases were removed from the data. That suggests that
other factors such as access to screening and treatment also play a role in the
disparity.
"Biology is only part of the puzzle," Carey said. "Access to health care is
very important."
Margaret Rosenzweig of the University of Pittsburgh School of Nursing, who
was not involved in the UNC study, said black women may be less likely than
white women to follow through on their treatment.
Rosenzweig and her colleagues, in a small study presented in Atlanta last
week at the annual meeting of the American Society of Clinical Oncology, showed
that poor black women with breast cancer had more difficulty understanding and
accepting their treatment than other racial and income groups.
"Clinicians in cancer care need to make a concerted effort to make sure black
women understand why they're getting the treatment they're getting and following
through with it," Rosenzweig said.