December 31, 2007
Minority Women, Breast Cancer & Hormone Replacement Therapy
Robert A. Wascher, MD, FACS
In 2002, the landmark Women’s Health Initiative Study reported that the long-term use of hormone replacement medications, consisting of two female hormones in pill form, was associated with a 26% increase in the relative risk of breast cancer (among other serious diseases as well, I might add). More recently, the Centers for Disease Control has reported a significant and unprecedented decrease in the incidence of breast cancer diagnosed in 2003. Other large scale public health studies, most notably from California, have also subsequently confirmed that a significant decrease in the incidence of breast cancer appears to be ongoing in the wake of the dramatic reduction in the use of hormone replacement therapy medications since the Women’s Health Initiative Study initial results were published in 2002.
But doubts persist in the minds of some who still will not accept any linkage between hormone replacement therapy and the risk of breast cancer, despite very solid data recently showing that the greatest reduction in the incidence of breast cancer has been for the type of breast cancer that is known to respond to the female hormones estrogen and progesterone. Indeed, it was about 5 years ago that I sat down and wrote a book that reviewed and analyzed decades-old (and more recent) scientific data that presaged the findings of the Women’s Health Initiative Study, and that unequivocally linked lifetime exposure to estrogen with a woman’s risk of developing breast cancer. The 5 decade monopoly of a single pharmaceutical company over the hormone replacement therapy “business,” and that company’s little-known history of sponsoring what amounted to disinformation campaigns about the safety of these medications is an important backdrop to the larger issue of hormone replacement therapy and cancer risk, and one that was extensively covered in my book as well. While the traditional print publishing industry has always been somewhat capricious and opaque, even to many publishing insiders, I was still not prepared for some of the responses that I received from major publishing house editors (most of them women). Many of these editors accused me of having some sort of intrinsic bias against hormone replacement therapy, and several implied, or overtly stated, that I must somehow have the misogynistic goal, as they saw it, of depriving women of the most effective available treatment for their menopausal symptoms. Taken aback that my efforts to educate women (and men) about a known—and preventable—risk factor for the most common cause of cancer in American women (and the second most common cause of cancer death in women, after lung cancer) were somehow perceived by publishing house editors as being anti-women, I shelved the project in disgust….
A new study in the journal Breast Cancer Research takes a look at recent trends in breast cancer incidence among minority women in the US, in the aftermath of the research findings that I have already mentioned, but which were based upon the study of predominantly American women of European descent. This study is important not only because it shines the light of clinical research upon ethnic minority women in the US, but because it also evaluated recent trends in breast cancer incidence according to sub-types of breast cancer, and in particular, hormone-responsive and non-hormone-responsive breast cancers.
Using the largest prospectively compiled cancer database in the US, the Surveillance, Epidemiology, and End Results (or “SEER”) cancer registry, the study’s authors analyzed SEER data from 1992 through 2004, and assessed the incidence of breast cancer among women from the following ethnic subgroups: Asian/Pacific Islander, Hispanic, African-American, and non-Hispanic White. Tumor hormone sensitivity status, tumor size, and other important tumor factors were also specifically analyzed.
The findings of this study are fascinating, and further implicate recent breast cancer incidence trends with changing trends in the prescribing of hormone replacement therapy following the 2002 release of the Women’s Health Initiative Study results. Specifically, the study found that the overall incidence of breast cancer declined significantly during the period of study in Asian/Pacific Islander (by 8.5%) and Hispanic women (by 2.9%), and was essentially unchanged in African-American women. These results are in comparison to the 14.3% decrease in the incidence of breast cancer noted, during the same period, for non-Hispanic white women. When the authors then looked at the trends for the incidence of non-hormone-responsive tumors in this same population of women with breast cancer, the findings were striking. The incidence of non-hormone-responsive breast cancers rose significantly among African-American women (26.1%) and Hispanic women (26.9%), who were already less likely to use hormone replacement medications than non-Hispanic white women before 2002, and who are even much less likely to use such medications now.
Taken as a whole, this study shows a trend towards fewer breast cancers in American women from minority ethnic groups, albeit not as pronounced as has been recently observed among non-Hispanic white women. At the same time that overall breast cancer incidence is declining in at least two groups of minority women (and is stable in a third group), the incidence of non-hormone-responsive breast cancers, which are not affected by hormone replacement therapy drugs, is increasing among the two ethnic minority populations of women that rarely use hormone replacement therapy drugs in the wake of the Women’s Health Initiative Study’s 2002 report.
While some who still do not see a link between hormone replacement therapy and breast cancer have proposed that a recent (and small) decrease in the number of mammograms being performed can somehow explain the unprecedented decline in breast cancer now being observed throughout North America (where, not coincidentally, the risk of breast cancer is among the highest in the world), the findings of this new study do not mirror recent trends in mammography when broken down by ethnicity. The findings of this new breast cancer study do, on the other hand, generally parallel the ongoing trends in the use of hormone replacement therapy drugs in postmenopausal women. Perhaps it’s time for me to dust off that old manuscript and have another look at it….
Reprinted by permission doctorwascher.com