Breast-Cancer-and-its-ill-effects-268x200Ageology clients who are investigating bioidentical hormone therapy (BHT) are often concerned that this therapy could increase their risk of developing breast cancer, based on what they’ve seen in the media on the subject.

That wave of negative hormone therapy press began in 2002, when researchers stopped one branch of the enormous Women’s Health Initiative (WHI) study. The study indicated that for every 10,000 postmenopausal women taking a combination of estrogen plus progestin (Prempro), eight more would develop invasive breast cancer than in a similar group not using hormone therapy (HT).  

At the time, about 13 million American women were using exactly this kind of HT, and in the next year, that number fell by half. Since that time, a once almost-universally recommended therapy for menopausal women—recommended because of its effectiveness at relieving menopausal symptoms like hot flashes, and because it helps preserve bone mass and reduces risk of colorectal cancer—is almost never prescribed in mainstream medicine. When it is prescribed, it’s given for the shortest possible time period, just to relieve symptoms until the transition to menopause is complete.

The hysteria around the WHI study failed to acknowledge a few important aspects of this story:

  • Many studies performed before that time demonstrated small increases in breast cancer risk with estrogen therapy alone, but a multiplied effect when synthetic progestins were added. Since this particular arm of the study was halted, parts of the WHI study that continued have found that estrogens alone are neutral or protective against breast cancer.
  • Women cannot receive estrogen-only HT if they have not had hysterectomies, because this creates a big bump in risk of endometrial cancer.
  • The problem with Prempro is its progestin component. Progestins are “fake” progesterone—crafted of molecules designed to occupy progesterone receptors, but that bear little resemblance to the real thing. They do the job they were added to HT to do, namely to prevent estrogens from causing endometrial cancer, but they don’t protect the breasts against estrogen’s proliferative effects the way real progesterone does.

So it would seem the logical next best step would seem to be to try more research into bioidentical progesterone, which preliminary studies show to be either neutral or beneficial to breast tissue when given with estrogens as a part of BHT.However, not nearly enough research dollars have gone in that direction, because bioidentical progesterone is not as profitable to pharmaceutical companies. It is available over the counter; in its transdermal form, which is its most commonly administered form, it can’t be patented, and so it doesn’t earn the profits Big Pharma desires.

Multiple studies find that bioidentical progesterone’s impact on breast tissue is quite different than the impact of progestins. I offer this evidence from Dr. Paul Savage’s soon-to-be published book, Betrayal: Women, Hormones and Health:

  • In one study, doctors applied transdermal estradiol and progesterone to the breasts of women about to undergo breast cancer surgery. In the 10-13 days of administration, estradiol was found to increase cell proliferation (a bad thing in terms of cancer) by 230%, but the progesterone decreased it by 400%, with a net decrease in proliferation (a very good thing in terms of cancer).
  • In the E3N cohort, a group of 80,000 postmenopausal women tracked for eight years while receiving either estrogen plus progestin or estrogen plus bioidentical progesterone, breast cancer was increased 69% in the first group, but did not increase at all in the second group.

Overall, we don’t know with 100 percent certainty that BHT cannot increase breast cancer risk. The choice to use it is a highly individual one, and should only be made via a careful choice process with an integrative metabolic medicine doctor who is thoroughly informed about current research.


Photo credit: Signs of Cancer