Saturday, August 09, 2003
The Lancet report was based on the ''Million Woman Study'' which surveyed 1,084,110 women in the United Kingdom aged 50 to 64. They were recruited between 1996 and 2001, and followed up for cancer incidence and death.
Professor Valerie Beral, director of the Cancer Research UK Epidemiology Unit and lead author of the study, said there was ''overwhelming evidence'' that the combination therapy was associated with a greater cancer risk.
Among 1,000 postmenopausal women who do not use HRT, there will be around 20 breast cancer cases between the ages of 50 and 60, Beral said.
In every 1,000 women who begin 10 years of HRT at the age of 50, there will be five extra cases among estrogen-only users and 19 among estrogen-progestin combination users, she said.
Dr. JoAnn Manson of the Harvard University Medical School commented that ''the evidence is now compelling that estrogen plus progestin is more deleterious to the breast than estrogen alone.''
Unfortunately, the full article isn't available without a subscription, but the abstract is:
1,084,110 UK women aged 50-64 years were recruited into the Million Women Study between 1996 and 2001, provided information about their use of HRT and other personal details, and were followed up for cancer incidence and death.
...Half the women had used HRT; 9364 incident invasive breast cancers and 637 breast cancer deaths were registered after an average of 2·6 and 4·1 years of follow-up, respectively.
The abstract doesn't make clear whether that was 9,364 total breast cancers out of the more than 1,000,000 women in the study or if that figure is just for the women who used hormones. Either way, it's an awfully small proportion. The rest of the abstract expresses the results only in terms of relative risk - which is meaningless in the face of such small numbers.
Meanwhile, here in the United States, the Women's Health Initiative people now say that hormone replacement therapy doubles the risk of heart disease:
"For American women who have been told that hormones are still safe if taken short-term, there was more bad news Thursday.
In a study published in the New England Journal of Medicine, researchers report that women taking a leading combination hormone therapy for menopause face nearly double the risk of a heart attack in the first year of use."
Here’s what the study actually found: 188 out of 8506 HRT users had coronary heart disease (defined as a heart attack, fatal or nonfatal). That’s just 2.2% of estrogen users. For non-users the incidence was 147 out of 8102, or 1.8%. Not much of a difference.
They then expanded the definition to include women who had symptoms of heart disease. But expanding the definition narrowed the gap even further. 369 out of 8506 users, or 4.3% had evidence of coronary artery disease, compared to 356 out of 8102 nonusers, or 4.4%. That's hardly a doubling of risk, now, is it?
Interestingly, another study in the same issue that involved measuring the degree of coronary artery stenosis over time, confirms that there's no difference in the progression of coronary artery disease between estrogen users and nonusers. But that study hasn't gotten nearly the press that the first one has.
The only thing that we can conclude from the studies done to date on hormone replacement therapy and the heart is that hormones don't prevent heart disease. And they don't appear to cause it, either.
posted by Sydney on 8/09/2003 10:47:00 PM 0 comments