Health care for women has been affected in many ways by our societies lack of full respect for women. This is true for Hormone Replacement Therapy. (Outside of the quotations from Estrogen Matters below, I will use that phrase to cover both estrogen only and estrogen plus progesterone treatments.) The conventional wisdom about Hormone Replacement Therapy beginning around the time of menopause has been affected by at least 4 forces: commercial incentives and suspicion of those commercial incentives, scientists who twist scientific evidence to further their preexisting views, ideological dogmas about “natural” being good, and underweighting of the importance of women’s quality of life.

The conventional wisdom is that Hormone Replacement Therapy (HRT) causes breast cancer. The big study on which the HRT-causes-breast-cancer conventional wisdom is based actually said something quite different. It said that even when a woman has been in menopause for many years without HRT, so that starting HRT up is a wrenching adjustment for the body, the effect on breast cancer can be precisely bounded as small. And there is no evidence that HRT begun smoothly at perimenopause causes breast cancer. Indeed, there is a lot of evidence that HRT begun smoothly at perimenopause has many positive health effects.

Avrum Bluming and Carol Tavris lay all of this out in their hard-hitting book, Estrogen Matters: Why Taking Hormones in Menopause Can Improve Women's Well-Being and Lengthen Their Lives -- Without Raising the Risk of Breast Cancer. One powerful analogy is that avoiding HRT in order to avoid breast cancer is like getting an unnececessary radical mastectomy in order to avoid a recurrence of breast cancer. Both are based on fear rather than on sound evidence of efficacy. They write:

Randomized trials and observational studies continue to show that breast-conserving surgery is almost always at least as effective as mastectomy. Yet rates of radical mastectomies, especially bilateral mastectomies, for treatment of localized breast cancer have been rising since 2006—another manifestation of the fear associated with breast cancer.

The idea that estrogen causes breast cancer is doubtful for many reasons. Here are some of them, as discussed in Estrogen Matters:

• Estrogen goes down at menopause, but breast cancer doesn’t go down. (Note that menopause is statistically distinguishable from age.)

• Estrogen is actually an important treatment for women with breast cancer.

• Early menarche and late menopause do not predict breast cancer.

• The endometrium is much more sensitive to estrogen than breast tissue. But no one is successfully claiming that HRT is related to endometrial cancer.

• “in most breast cancers, estrogen-receptor-positive cells are not the ones proliferating.” If a breast cancer cell is estrogen-receptor-positive, that is an indication that it is more like a normal breast cell than cancer cells that are estrogen-receptor-negative.

• Pregnancy, which dramatically raises estrogen levels, is not a risk factor for breast cancer.

The false belief that Hormone Replacement Therapy begun as usual around the onset of menopause causes breast cancer is extremely damaging because HRT has many powerful benefits. Here is Avrum Bluming and Carol Tavris’s summary of those benefits near the beginning of Estrogen Matters, with my emphasis added in bold:

Estrogen not only successfully controlled menopausal symptoms in most women but also significantly reduced the risks of heart disease, hip fractures, colon cancer, and Alzheimer’s. A 1991 New England Journal of Medicine editorial, “Uncertainty About Postmenopausal Estrogen: Time for Action, Not Debate,” reported a 40 to 50 percent reduction in atherosclerotic heart disease, which was responsible for the deaths of more than eight times as many American women as breast cancer. The long-running Framingham study reported a 50 percent drop in osteoporosis-associated hip fractures, which were linked to as many deaths every year as breast cancer. Two studies, one from the University of Wisconsin and one from the American Cancer Society, reported a 50 percent decrease in the risk of developing or dying of colon cancer. And a USC study reported a 35 percent decrease in the risk of Alzheimer’s. Among women with no history of breast cancer, studies found that estrogen did not increase the risk of developing it, even among women who had been taking estrogen for ten to fifteen years. Most remarkable, women taking estrogen were living longer than women who were not taking hormones. A 1997 report in the Journal of the American Medical Association stated that “HRT should increase life expectancy for nearly all postmenopausal women by up to 3 years.” Their analysis concluded that up to 99 percent of current postmenopausal women would benefit from taking HRT as measured by decreased rates of disease and improved longevity.

Even if, contrary to the evidence, Hormone Replacement Therapy begun as usual around the onset of menopause did have any substantial effect on breast cancer, that should not overrule all the other benefits. It is difficult to do, but breast cancer should be kept in perspective. As Avrum and Carol write:

The often repeated statistic that one woman in eight (12 percent) will develop breast cancer at some point in her life should be understood in a broader context: That’s a woman’s risk of getting it, all right, but only if she lives to be eighty-five. As Patricia T. Kelly explained in Assess Your True Risk of Breast Cancer: • A thirty-year-old woman has a risk of developing breast cancer in the next decade of 1 in 227 (0.4 percent). • A forty-year-old woman has a decade risk of 1 in 68 (1.5 percent). • A fifty-year-old woman has a decade risk of 1 in 42 (2.4 percent). • A sixty-year-old woman has a decade risk of 1 in 28 (3.6 percent). • A woman over seventy has the highest risk, 1 in 26 (4 percent).1 So where did that one-in-eight risk come from? It’s obtained by adding together the risks in each age category: 0.4 plus 1.5 plus 2.4 and so forth. But if you are a woman who has reached age sixty without a diagnosis of breast cancer, your risk in the coming decades is only 7.6 percent (12 percent less each decade’s risk that you have passed); the risk of breast cancer in any given decade of life never exceeds one in twenty-six. Yet by far the most important statistic is this one: over 90 percent of women currently diagnosed with early breast cancer will be cured, and most will not need disfiguring mastectomies or chemotherapy.

Dangers surround us, and death is coming for us all. We need to choose our battles out of a much larger set of concerns than breast cancer alone.

Every woman and every man who cares about a woman should read Estrogen Matters. (I listened to it on Audible.) Even if you are already convinced that HRT is the way to go, you are going to need to be armed with a fairly detailed knowledge of the science in order to stand up to your doctor, who is likely to adhere to the conventional wisdom on HRT. Note that Avrum Bluming is just as much an MD as your doctor, and for most of us, much smarter than our own doctor. And he and Carol Tavris lay out the evidence and logic in a much more detailed way than your own doctor is likely to be able or willing to do.

Note: HRT is an important enough issue, I expect to return to this topic and discuss more of what is in the book Estrogen Matters in future posts.

For organized links to other posts on diet and health, see:

• Miles Kimball on Diet and Health: A Reader's Guide