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.
SAN ANTONIO--Two poster presentations at the San Antonio Breast CancerSymposium suggest that breast tumors are more aggressive in African-Americanwomen 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 cancerpresenting to the GWU Cancer Center between January 1987 and December 1994were all staged in the same way and generally went through the same treatmentprotocols, and yet the African-American women did not do as well in termsof survival as the Caucasian patients.
Survival among patients with stage II/III disease was significantlyshorter in the African-American group, and there was a trend toward shortersurvival of African-Americans among the stage I patients. An examinationof markers for aggressiveness showed that the African-American women weremore likely to have a high tumor grade and to be estrogen/progesterone-receptornegative.
"Those were the two most striking factors, but in terms of otherassays such as S phase and ploidy, there was also a tendency for the African-Americanwomen to have more abnormal values," said Paul H. Levine, MD, of theGeorge Washington University Cancer Center.
The researchers feel that African-American women as a group have moreaggressive 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, overtime, the rate of aggressive breast tumors dropped from about 50% initiallyto about 20%, presumably due to some change in the environment, possiblynutritional.
"Now that we are, I think, documenting biologic differences inthe tumors, we're going to look at the risk factors and see why African-Americanwomen generally have more aggressive breast tumors than Caucasian women,"he said.
In the second study, from the Comprehensive Cancer Center of Wake ForestUniversity, Winston-Salem, NC, no differences in ER/PR status were foundbetween the African-American and Caucasian patients, and, in fact, to datethere 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-Americanwomen as you get out to 10 years of follow-up." In addition, the African-Americanwomen had a significantly shorter time to relapse.
A More Select Population
The patients in the Wake Forest study were a more select populationthan the George Washington University group, Dr. Little pointed out. Theywere all stage II breast cancer patients who had received the same chemotherapyregimen 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 therewere differences in tumor grade between the two populations, and, if so,that may account for the trend toward poorer survival in the African-Americangroup."