SAN ANTONIO--Two poster presentations at the San Antonio Breast Cancer
Symposium suggest that breast tumors are more aggressive in African-American
women than in Caucasian women.
In the first study, a joint project of the National Cancer Institute
(NCI) and George Washington University (GWU), 862 women with breast cancer
presenting to the GWU Cancer Center between January 1987 and December 1994
were all staged in the same way and generally went through the same treatment
protocols, and yet the African-American women did not do as well in terms
of survival as the Caucasian patients.
Survival among patients with stage II/III disease was significantly
shorter in the African-American group, and there was a trend toward shorter
survival of African-Americans among the stage I patients. An examination
of markers for aggressiveness showed that the African-American women were
more likely to have a high tumor grade and to be estrogen/progesterone-receptor
"Those were the two most striking factors, but in terms of other
assays such as S phase and ploidy, there was also a tendency for the African-American
women to have more abnormal values," said Paul H. Levine, MD, of the
George Washington University Cancer Center.
The researchers feel that African-American women as a group have more
aggressive tumors than Caucasian women and that it is a biologic effect,
rather than being due to a delay in diagnosis, Dr. Levine said.
He also believes that heredity is not a major factor in the difference.
This conclusion is based in part on studies in Tunisia showing that, over
time, the rate of aggressive breast tumors dropped from about 50% initially
to about 20%, presumably due to some change in the environment, possibly
"Now that we are, I think, documenting biologic differences in
the tumors, we're going to look at the risk factors and see why African-American
women generally have more aggressive breast tumors than Caucasian women,"
In the second study, from the Comprehensive Cancer Center of Wake Forest
University, Winston-Salem, NC, no differences in ER/PR status were found
between the African-American and Caucasian patients, and, in fact, to date
there has been no significant difference in overall survival.
"However," said Vinnette Little, MD, who presented the data,
"we did see a trend toward poorer survival in the African-American
women as you get out to 10 years of follow-up." In addition, the African-American
women had a significantly shorter time to relapse.
A More Select Population
The patients in the Wake Forest study were a more select population
than the George Washington University group, Dr. Little pointed out. They
were all stage II breast cancer patients who had received the same chemotherapy
regimen and had met the same inclusion criteria for the study.
"This may account for the fewer differences seen in our study,"
she said. "We would have to do further study to see whether there
were differences in tumor grade between the two populations, and, if so,
that may account for the trend toward poorer survival in the African-American