New research shows a significant drop in
In April 2002, a large trial suggested that the combination
of estrogen and progestin used to treat menopause symptoms raised the risk of
breast cancer and heart disease. Therefore, many women stopped using hormone
replacement therapy, which resulted in a sharp decreasing of breast cancer rates
during 2002 and 2003. However, this decline was confined to Caucasians, the
researchers reported.
In women in the age group from 50 to 69 those more likely
to use hormone-replacement therapy we found that the reduction in invasive
breast cancer with estrogen-receptor positive tumors was like 13 percent for
whites, 11 percent for Hispanics, about 4 percent for Asian of Pacific Islanders
and no change for African-Americans, Dezheng Huo, an epidemiologist at the
University of Chicago Medical Center and lead author of the study, said as
quoted by the Washington Post.
Huo and his colleagues based their study on data from 17
cancer registries, covering about 26 percent of the
The researchers blamed the differences in biology for much
of the racial disparity. We suspect that the widespread discontinuation of
menopausal hormone use had a greater effect on Caucasians, Huo said. Black
women have less estrogen-receptor positive cancers, and so the decline in HRT
use might not have such a dramatic effect on their cancer, he speculated.
Another reason that might be responsible for the racial differences could be that black women may have used HRT less frequently than white women, and so again would not be as affected by the declining use of hormones.
Almost 80 percent of breast cancers in Caucasians are estrogen receptor positive, a type of tumor that depends on estrogen to grow, said Huo, compared to about 60 percent in African Americans. That proportion drops to about 30 percent among Nigerian women.
The research was supported by Breast Cancer SPORE grant from the National Cancer Institute.