No.
Estrogen does not cause the cancer.
But in my head, I always felt like if a tumor is estrogen receptor positive, that giving it estrogen is like feeding it. It makes sense to me that women are given ANTI estrogens as part of their cancer treatment. Your cancer needs estrogen to grow? We are taking that all away. But the book I am reading states it does not feed the cancer. So what is the answer?
In my deep dive into estrogen and hormone replacement therapy, reading multiple sources and going frequently to PubMed to search for articles published in medical journals, I am finding studies on both sides of the fence. It is important to try to suss out the “fake news” in medicine. Reading one book by an impassioned author where they cite studies is compelling. But there is another side.
Confused? I am.
In reading my Estrogen Matters book, clearly a group in the pro-estrogen side, they go through a litany of studies and points. Some I found interesting:
- There are some studies where giving patients with breast cancer estrogen can improve survival. One study out of the Mayo Clinic showed better survival among breast cancer patients when given estrogen over tamoxifen. This is a hard one for me to wrap my head around, as we give any woman who has an estrogen receptor positive tumor Tamoxifen (an anti-estrogen).
- Most published reports do not show a consistently increased risk of breast cancer if doing estrogen replacement- 82% found no increased risk, 13% found a small increased risk, 5% found decreased risk
- The majority of breast cancer patients have not taken estrogen
- The risk of breast cancer increases as you get older, even though your estrogen levels decline as you age.
- Those who get their periods early do not have higher rates of breast cancer.
- The percentage of breast cancer patients who have used HRT is 11-24%. 90% are cured
When the infamous WHI study found breast cancer rates declined after they warned HRT caused breast cancer, they advocate there were flaws in the study.
- First, the decline started in 1999, 3 years before they warned to stop HRT
- Second, Sweden and Norway stopped HRT, but did NOT have a decreased in breast cancer rates
- Third, breast cancer takes years to become detectable (meaning you have the cancer for years before we can see it on mammogram or you have a lump).
But when I go to PubMed and search for “hormone replacement” for breast cancer patients, I see a ton of studies on Tamoxifen, and Aromatase inhibitors. I don’t see studies on giving breast cancer patients hormone replacement.
As just one example, getting out of our United States medical bubble, I found a French Study from 2008, which concludes hormone replacement increases breast cancer risk, whether estrogen alone or combined therapy, and regardless of oral or patch:
“Large numbers of hormone replacement therapies (HRTs) are available for the treatment of menopausal symptoms. It is still unclear whether some are more deleterious than others regarding breast cancer risk. The goal of this study was to assess and compare the association between different HRTs and breast cancer risk, using data from the French E3N cohort study. Invasive breast cancer cases were identified through biennial self-administered questionnaires completed from 1990 to 2002.
- During follow-up (mean duration 8.1 postmenopausal years), 2,354 cases of invasive breast cancer occurred among 80,377 postmenopausal women.
- Compared with HRT never-use, use of estrogen alone was associated with a significant 1.29-fold increased risk
- The association of estrogen-progestagen combinations with breast cancer risk varied significantly according to the type of progestagen:
- the relative risk was 1.00 for estrogen-progesterone,
- 1.16 for estrogen-dydrogesterone, and
- 1.69 for estrogen combined with other progestagens. This latter category involves progestins with different physiologic activities (androgenic, nonandrogenic, antiandrogenic), but their associations with breast cancer risk did not differ significantly from one another.
- This study found no evidence of an association with risk according to the route of estrogen administration (oral or transdermal/percutaneous).
- These findings suggest that the choice of the progestagen component in combined HRT is of importance regarding breast cancer risk; it could be preferable to use progesterone or dydrogesterone.”
So my thoughts?
Again, I keep coming back to basics. What is your risk tolerance? Do you have dense breasts or an increased risk of breast cancer? Do you have clotting issues? How bad are your menopausual symptoms? Are you at high risk for heart disease, bone fractures, alzheimers? Do you have strong menopause issues like depression, hot flashes, and poor sleep?