The Million Women Study is a British observational study that began in May 1996 and ended in December 2001. Women were 50-64 at the time the study began, and their numbers included one in four of all women in this age group in Great Britain at the time.

The latest report to describe the fate of these women reveals more disturbing news about the risks of hormone therapy and breast cancer. The study appeared in the January 28, 2011 issue of the Journal of The National Cancer Institute and a report about it appeared in last Friday’s edition of the New York Times. There, it joined a long list of articles that describe an ever-escalating concern about the use of systemic hormone therapy.

There has been some interest in the timing theory, which has promoted the idea that women given systemic hormone therapy early in their menopausal transition were less likely to suffer from the cardiovascular complications (blood clots, strokes and heart attacks) and perhaps less likely to have an increase in breast and endometrial cancer.

While this observational study does not carry the scientific weight of those, like the Women’s Health Initiative, that are prospective, randomized, and compare their subjects to control subjects, the sheer numbers of women involved, and the time that has elapsed since the women were enrolled in the British study, are important.

The findings revealed that the lowest number of women who developed breast cancer since beginning the observational study were those who did not take any hormones, followed by those who began hormone therapy after five years past menopause. The highest rate of breast cancer was found in the group who began hormone therapy when they were most likely to be symptomatic—just before or within five years of menopause. The length of time that hormones were used, and the impact this had on the future development of breast cancer, were not as clear.

However, it is clear that each woman who chooses to use systemic hormone therapy must do so knowing that right now, the only certainty is that the medical and scientific community cannot even state how long a woman can use the lowest dose possible of systemic hormone therapy to control her symptoms without increasing her risk of breast cancer.

The only comfort that practicing physicians and their patients can take from all of these reports is that the real risk of developing breast cancer with the short-term use of systemic hormone therapy is low.

This continual emergence of data from important scientific studies remains in stark contrast to the marketing barrage from the “bio-identical hormone” industry, which claims that systemic hormone therapy that is compounded by special pharmacists does not have any side effects, including no increase in breast or uterine cancer.

Until the FDA investigates the claims of these purveyors of hope for women who want relief from their symptoms, doctors will be besieged by patients who call asking if the doctor prescribes “safe” bio-identical hormones.

Hello Washington! We need a little help here on the front lines.