Q & A: HRT and Breast Cancer Risk
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HRT and Breast Cancer Risk

Q: Does combining of estrogen and progestin significantly increase the risk of breast cancer, as reported in a January 2000 JAMA article? How important are individual studies in personal treatment protocol decisions?

While I have not read that one, I have done so with several other studies that get into to medical literature. I am left with the distinct impression that "Medical Research" is an oxymoron. Too often, half-baked correlations (the probability that two things happen together) is wrongly interpreted as causation (one thing can produce the other). This is fallacy of the worst kind, and most Master's programs in any science would throw you out for proposing this in your thesis. Most medical journals, however, will publish it.

So, for example, HRT cuts a woman's chances of a heart attack (biggest killer of women past menopause) in half. Saves a lot of lives. But, the older you get, the more likely you are to get breast cancer. So, on one big survey the medical people followed women on HRT. Since many more were alive to get cancer and other things at the end of 10 years, more were dying. So, the medical people claim that HRT only helps for 10 years.

Or likewise, French people don't seem to have as many heart attacks as were expected. Another correlation, and presto, they are calling a press conference to announce that it is all the wine the French drink that save their hearts. Never mind that there are millions of other differences.

HRT, progesterone, and cancer? Well, HRT cuts your heart attack risk in half, so more women will be around to develop breast cancer. No matter what you do to or for a women, about one in eight will get breast cancer. The last 20 years have been looking at HRT (mostly with the very alien horse estrogens) to look for an effect. No two studies have agreed. The most condemning ones say that it goes up to one in seven. Most are unable to state a clear effect (if you count out the women who would be dead from heart attacks), and a few suggested a protective effect. All kind of vague. And, if all you do is look at self-selected groups, you will never be able to get any closer to cause and effect.

Avoid natural progesterone? If I were a woman, that would be the last thing that I would think about doing.

  1. Estrogen, in post-menopausal women, without a progestin or progesterone will, most likely, lead to endometrial hyperplasia in about a year or two (depending on a lot of variables). This amounts to a written invitation for a D&C.
  2. Keep up the estrogen and no progesterone for a few years, then your chances of endometrial cancer starts to climb into a range that we are unable to find elsewhere.
  3. The progesterone belongs in your body, does not negate estrogen's beneficial effect on lipids like progestins do, and actually increases bone density. A lot of women die before their time from hip fractures and osteoporosis.

I feel that, even in women who are not taking estrogen, taking progesterone is a cheap insurance policy that can protect your endometrium and possibly other tissues from unopposed natural estrogens and the sea of xeno estrogens that we swim in.

Don Michael, MD


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  Disclaimer: Opinions expressed here are for informational purposes only and do not constitute a physician-patient relationship. The information should not be considered as medical advice or as a substitute for a visit to your healthcare provider. You are strongly encouraged to seek the advice and supervision of a physician or other certified practitioner regarding any medical issue.








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Updated 09/29/2010