Although breast cancer rates are on the decline, a new study shows that some groups have seen a more significant decline than others. The study suggests that race, ethnicity and economic background play a part in the rate of that decline.
The study, which appears online and in the American Journal of Public Health, reports that the only significant decline in breast cancer rates occurred among white, non-Hispanic women, aged 50 years and older, who live in high-income counties and who have the kind of tumors that an estrogen-rich environment will nourish. For this population, rates have declined by as much as 10% annually.
The study relied on data obtained from 13 U.S. population-based cancer registries for 1992 to 2005, and analyzed trends among 350,000 cases. Researchers looked at race/ethnicity and socioeconomic situation in addition to age at diagnosis and tumor characteristics.
According to a news release, in 2002, the Women’s Health Initiative (WHI) study prompted many doctors to stop prescribing hormone therapy when the findings contradicted the previously held assumption that estrogen/progestin replacement therapy would lower a woman’s risk of heart disease.
The findings of WHI suggested the opposite — that hormone therapy actually would increase the risk of heart disease and breast cancer. According to a press release, this new study on breast cancer trends did not have access to information on individual women’s hormone therapy use, however, the same group of women who exhibited the most significant decline in breast cancer rates was also the group most likely to have been taking hormones before the WHI.
“In these other groups, which were much less likely to have been prescribed hormone therapy, one did not see a drop in their breast cancer rates,” Nancy Krieger, PhD, lead study author and professor in the department of society, human development and health at the Harvard School of Public Health, told O&P Business News. “This means that it should not be assumed everyone’s risk of breast cancer is dropping equally, it is dropping for those who can stop exposure to hormone therapy.”