The Seattle Times published a story today with the headline, “Study chips away at hormone therapy” (online: “Breast cancer rates fell with drop in hormone therapy, study says”) This is my response.
This study does not “chip away at hormone therapy” — although it may chip away at the use of pregnant mare’s urine as the building block for HRT. Prempro and Premarin are not the only forms of hormone replacement — but they seem to be the only ones studied in the US. And I’ve yet to see a reporter note that the study they are writing about is restricted to these two drugs. Or that research linking the foreign bodies in these drugs to breast cancer began in the 1990s.
What does the report actually say? “Use of estrogen and progestin therapy for 5 or more years is a relatively modest breast cancer risk factor … a decline in use of estrogen and progestin therapy would need to be large … to result in a sizeable decline in ER-positive invasive breast cancer.” And that risk is just for women with a uterus.
I’ve also yet to see a reporter explain why there are two drugs — the combo is for women with an intact uterus. By age 60, 1 in 3 American women have had a hysterectomy. But this study did not differentiate between women who had a uterus and women who did not. It also did not discriminate between new and former HRT users. Thus, it is would be flawed if it were designed to examine the correlation between HRT and breast cancer. But that wasn’t its purpose, as its summary makes clear: “a decline in screening mammography rates is unlikely to account for the recent decline in US breast cancer incidence.”
Finally, over the same period of time, women in Britain also reduced their use of HRT. But they had no parallel decline in breast cancer rates. That little tidbit is missing from the Times story as well. Of course, more women in Europe use a bio-identical estrogen patch than do women in the US. It costs significantly more than Prempro/Premarin.
I have some old writings on HRT research that I need to get back online — they vanished when I closed my Typepad account.