The most recent research found that synthetic estrogen (taken without synthetic progesterone) does not increase the risk of breast cancer. There’s also a hint, consistent with research I’ve read, that the risky culprit in hormone replacement therapy for women may be synthetic formulations of progesterone (progestins). From an April 12th, 2006 article in the Washington Post Estrogen Alone Does Not Increase the Risk of Breast Cancer. (You may have to register to read it but it's free. )
The seven-year study of more than 10,000 women, the biggest, best-designed study to examine the risks of hormone therapy, found no evidence that estrogen alone increased the danger of developing the common malignancy, and produced evidence it may protect some women against the tumors. Earlier research had indicated the hormone raised the risk…."The jury is now in: Estrogen does not increase the risk for breast cancer, which is what most women thinking about using the hormone worry about," said Marcia L. Stefanick of Stanford University…
Not only was there no overall increased breast cancer risk among the women taking estrogen, the researchers found, but also there appeared to be somewhat fewer breast cancers among those taking the hormone -- 28 per 10,000 vs. 34 per 10,000 in the placebo group.
The findings suggest that it is progestin, not estrogen, or perhaps the combination of the two, that increases the risk of breast cancer. "Progestin is definitely a top suspect," Stefanick said.
The risk of blood clots is also lower among women taking estrogen alone, compared with taking estrogen and progestin, said Jacques Rossouw of the National, Heart Lung and Blood Institute, which runs the Women's Health Initiative.
"It's definitely beginning to look like it's the progestin component," Rossouw said. "There's just too many things piling up."
Here’s some additional information about synthetic progesterone (progestins) that hints they may be problematic.
Mechanisms of Progesterone Induced Neuroprotection
we comment on the need to carefully consider the various preparations of progestins that are currently available and argue that "not all progestins are created equal," at least when it comes to influences on neuroprotection.
Progesterone and “Progestin”
Progestins Initiate Adverse Events of Menopausal Estrogen TherapyThe recent results from the Women's Health Initiative trial, which used MPA as the progestinal agent, indicate that differences between progestin formulations are crucial to health outcomes in women.
RESULTS: In both peripheral and cerebral vasculature, synthetic progestins caused endothelial disruption, accumulation of monocytes in the vessel wall, platelet activation and clot formation, which are early events in atherosclerosis, inflammation and thrombosis. Natural progesterone or estrogens did not show such toxicity. CONCLUSION: The risk associate with combined estrogen plus progestin therapy may be a consequence of vascular actions of progestins.
This final link, Hormone Therapy UVA Update 2004 provides, IMO, an understandable presentation of the risks from the earlier WHI studies. These studies were with synthetic hormone preparations. There’s a nice table of the risks/benefits on page 10 of the estrogen + progesterone and estrogen only trials. Quoting from the update:
Without more data, it is not possible to make specific recommendations about other hormone medications, including compounded “natural” products. Without scientific clinical trial data, one cannot assume that alternative estrogen plus progesterone treatments have the same risks or are any safer than those studied in WHI.
I think it’s always difficult to make decisions regarding the risks/benefits one is willing or not willing to take and I hope this information is helpful. It’s unfortunate that there’s really been no research on the risks of “bioidentical” or naturally compounded hormones post menopause. The risks may be more, less or equal to the synthetics. It certainly seems to me though that at this point even the synthetic estrogen may not present as many risks as originally suggested and synthetic “progestins” may be particularly problematic.
Take care everyone…and, sorry guys, this one really wasn’t for you.