There’s a lot of confusion out there when it comes to the topic of progesterone and breast cancer. About 70% of breast cancers are ER+ (estrogen receptor-positive), and most of these breast cancers (about 87%) are also PR+ (progesterone receptor-positive).
Hormone receptor status has long been a main factor in considering breast cancer treatment. Many women worry when they hear that their breast cancer is both ER+ and PR+, believing this to be “double trouble.” It is time to set the record straight.
Actually, doctors have known for a long time that women with high levels of both estrogen and progesterone receptors (high ER+ and PR+ status) often have the best chance of surviving. Despite this, it appears that some oncologists may not really understand or explain one very key point…
While estrogen can fuel a tumor’s growth, progesterone puts the brakes on that growth. Hence, they leave patients in a sea of fear and confusion unnecessarily.
What are Estrogen and Progesterone Receptors, and What Do They Do?
Estrogen and progesterone receptors are proteins found within many of the cells of our bodies, including cells in the breasts. Both receptors are directly involved in switching genes on and off − some 470 different genes. When estrogen and progesterone are present, these hormones stick to their respective receptor. They can then attach to specific regions of our DNA and turn genes on or off, changing the cell’s behavior.
Hormone receptor-positive breast cancers have many hormone receptors. When breast cancer develops, the tumor cells become overly sensitive to estrogen. When estrogen activates the estrogen receptor, it turns on a panel of genes that tell the cells to keep dividing, driving tumor growth. However, when breast cancer cells have working progesterone receptors, and there is sufficient progesterone available, progesterone will slow down estrogen fueled growth and division of these cells.
The late John Lee, MD, author of What Your Doctor May Not Tell You About Breast Cancer, was on to this years ago. He maintained that when activated by progesterone, the progesterone receptors attach themselves to the estrogen receptors.
Once this happens, the estrogen receptors stop turning on genes that promote the growth of the cancer cells. Instead, they turn on genes that promote the death of cancer cells (known as apoptosis) and the growth of healthy, normal cells. Yet few seem to have been paying attention to his advice. Therefore, many doctors continue to villainize progesterone and progesterone status.
New Study Highlights Benefits of Progesterone
Hopefully a study published in the Dec 2016 edition of the journal Nature, led by Cambridge-based Cancer Research U.K. researcher Dr. Jason Carroll of the University of Adelaide in Australia, brings more credence and awareness to the benefits of progesterone and progesterone receptor-status.
The presence of both ER and PR status has typically been considered an indication of how good a woman’s chances of surviving were. The belief being these cancers were more “treatable” than hormone receptor-negative cancers.
But in Dr. Carroll’s study, the scientists confirmed the “why.” They found that progesterone – via the progesterone receptor – is somehow affecting how the estrogen receptor works. Interestingly, they found that the progesterone receptor, in effect, “reprograms” the estrogen receptor, changing the genes that it influences.
But, the most important part was the overall effect this has on the cancer cells themselves. Progesterone seemed to cause the cells to stop growing as quickly. Dr. Carroll’s findings further explain why the receptor itself is the direct reason why women who have both ER+ and PR+ have a better outlook than those with just ER+ or receptor-negative cancers.
The Role of HER2 and Progesterone in Breast Cancer
Two other recent studies suggest that metastatic dissemination of tumor cells prior to the detection of a primary tumor is regulated via HER2 expression and progesterone signaling. By implicating progesterone in the development of early metastasis, one could infer that progesterone is bad.
However, it is this author’s opinion that it is important to understand the difference between progesterone that is made by the human body and synthetic progesterone, which is unnatural to the body.
Progesterone is a key physiologic hormone of women. But while natural progesterone has an anticancer effect, synthetic progesterone (found in birth control pills and hormone replacement supplements) does not. For example, research shows that the synthetic version progestin (medroxyprogesterone) is not only linked to breast cancer, but that those cancers tend to be “more aggressive and deadlier.”
Furthermore, researchers have known for some time that synthetic progesterone does not stimulate activation of the tumor suppressor gene p53 when it attaches to progesterone receptors.
P53 is a repair gene, which protects cells from becoming cancerous. It is the primary gene that protects women from breast cancer. In order for progesterone to facilitate the production of p53, it must attach itself to progesterone receptors.
If synthetic progesterone (again, which does not stimulate the production of p53) is present on the receptors, natural progesterone will not be able to occupy the receptors.
Clearly, it would be a good idea to down-regulate HER2, maintain healthy progesterone levels, and avoid synthetic progesterone. (While Herceptin is the drug of choice for HER2, daily consumption of 25 grams of flaxseed has been shown to decrease HER2 expression by 71%, which appears to outperform the drug, sans the damaging effects of drugs.).
Doing so could not only increase the chances of recovering from breast cancer, but could also help avoid getting breast cancer in the first place.
You are now empowered with the truth about progesterone and breast cancer. Please share this vital information with friends and family who could benefit.
Article Summary
Women with high levels of both estrogen and progesterone receptors often have the best chance of surviving cancer.
Progesterone will slow down estrogen-fueled growth and division of tumor cells.
Studies found that the progesterone receptor, in effect, “reprograms” the estrogen receptor, changing the genes that it influences.
While natural progesterone has an anticancer effect, synthetic progesterone does not.
Synthetic progesterone is not only linked to breast cancer, but those cancers tend to be “more aggressive and deadlier.”
If synthetic progesterone is present on the receptors, natural progesterone will not be able to occupy the receptors.
Thanks a lot – on the cansurviving site we have a song called ‘Take a Look Outside the Box’ written for us several years ago–people can get DAZED and CONFUSED and we have a forum called Where can I start? which helps people slow down and do things one at a time rather than become overwhelmed with information, all good but nevertheless at lot to take on when your are already traumatized.. cansurvivors unite….
My tumor was very close to TNBC, but the progesterone receptor was weakly (16%) positive. I have refused chemo and hormone therapy and instead am opting for a big step up in diet, exercise, supplements, etc. However TNBC’s re-occurrence terrifies me…not that I am second-guessing my decision to not do chemo or the hormones, but I have heard even Naturopaths say that TNBC doesn’t respond to natural alternatives. I did have lumpectomy, clear margins (1.5 cm tumor, .8 cm was cancerous) and microscopic cancer in one node with no evidence that it had spread. What is a good treatment, besides eating the rainbow and all that good stuff that I am doing, for TNBC? I will also do quarterly thermograms.
Hi Susan,
The best advice we can give you is to consult with one of the doctors/experts that we interviewed in our Global Quest Series. Here is a link to get their information: https://thetruthaboutcancer.com/experts-info-sheet/
Dr. Judith Edwards,what type of tests that a woman can do to indicate whether she has high progesterone levels or not? What tests can you do to indicate whether a woman will get breast cancer in the future or not?
I was diagnosed with endometrial cancer going on three years ago. I don’t know that I was tested for “receptors,” but the surgeon suggested my being overweight probably caused me to be more estrogen dominant, a leading factor. I researched this online, after my surgery, a radical hysterectomy. I was very disappointed that my ovaries were removed, which were clean, along with 15 lymph nodes. I was able to refuse chemo and radiation, afterwards. My point is, there were studies, but only of pre-menopausal patients, indicating that there was no higher rate of re-occurrence in women who did NOT have their ovaries taken. Also, there is a study that showed women who used birth control pills, which balance estrogen with progesterone, have had a lower rate of this type of cancer, lower than women who didn’t have that added progesterone.
Doctors have standardized treatments, generally, and aren’t open to exploring other protocols. I lost a lot of weight, by changing my diet and working on a daily exercise routine. My health is much better. I have to make the most of the days I have left. Sometimes I feel “separation anxiety” over the body parts which were taken from me; I did sign consent for the surgery, but under a great deal of pressure. I’m so grateful I chose not to endure radiation and chemo, which my research, and my gut feelings (intuition), plus tons of anecdotal evidence from friends and family members, was telling me would only increase the chances that another cancerous tumor could reoccur.
I just watched a great series called SquareOne at Chrisbeatcancer.com. Chock full of good information on beating cancer with diet using mostly fruits and vegetables.
Unfortunately this information about breast cancer and progesterone did NOT address the bio-identical version of progesterone which is also supposed to be “protective”. Would anyone care to clarify this for us? Thank you…
This is the info I am looking for as well!! Please let us know, I’m terrified!!
I used bio-identical progesterone cream for over a year until my levels corrected themselves naturally. It was a life saver – and I believe literally. I first used John Lee’s cream and then had a naturopath write a prescription – fulfilled by a local compounding pharmacy. I was surprised that my own OB/GYN doctor who is NOT a naturopath agree to continue the prescription.
Does bio identical progesterone act in the same way as natural progesterone or synthetic progesterone?
Great article. BUT!! You did not tell how I can get real progesterone.
Ask your Dr. for a prescription for Bio-identical progesterone. It is compounded. Or you can order online through John Lee’s website, but dosage is not as accurate.
Hi! Have you read dr Soderbergs rerearch for Karolinska that 100% of breast tumors and some 97% of brain tumors infected with the CMV virus , along with its metastases? And when treated for CMV wiith Valcyclovir for mor than 6 monts, 90 % of the patients !!! were still alive after 2 years compared to a fraction who didnt recieve it alongside traditionell cancer terapy.
Hi astenbom, would this info be on our pathology reports?
I would like to ask the author of the article why they recommend taking flax seeds for prevention//treatment of breast cancer. I was ER+ but I boycott flax seeds/linseeds due to their phytoestrogen content?
I had a hysterectomy a few years back and everything was removed. I am taking synthetic estrogen to keep the hot flashes away. Does my risk for breast cancer go up because of the synthetic estrogen in taking?
I am confused, I had a estrogen receptive cancer and was avoiding flaxseeds due to the estrogen like abilities. Are you saying that consuming flaxseeds is good for me? Does the flaxseed contain the natural progesterone?
Please advise, as the end of the article is confusing and I cannot make much sense of it.
Thank you,
Teresa
I would also like to know about bio-identical progesterone. You seem to say they are all the same? I am a 27 year survivor and have used bio-identical progesterone for 20 years now.
None of the studies/resources listed discuss flax seed use. Can we see the research behind using this for progesterone? As others have stated, it’s known for its estrogenic qualities.
I think the role of progestins and progesterone and breast cancer is complicated. A synthetic progestin, medroxyprogesterone acetate, had previously been used with some success in slowing metastatic breast cancer before tamoxifen. These were probably ER/PR positive breast cancers. But when you throw HER2 into the mix things get complicated. HER2 is a receptor and while it doesn’t have a known ligand (triggering agent) of it’s own, when other types of HER receptors are triggered by their ligands, they tend to bind to HER2 and trigger HER2. One of these ligands is amphiregulin, which is a ligand for HER1 also known as EGFR. The expression of amphiregulin is thought to be induced by progesterone. I can’t comment on the difference between natural progesterone and the various synthetic progestins in this process, but at least one study found that high serum amphiregulin levels were associated with early disease progression and trastuzumab resistance. Another study found that amphiregulin silencing reduced the invasive capacities of one breast cancer cell line, SKBR3 (ER/PR negative, HER2 amplified), but not two other cell lines, BT474 (triple positive with a TP53 mutation), and HCC1954 (ER/PR negative, HER positive). I wish I could be more illuminating but that’s all I’ve got right now.
In 2015 I was treated for ER+, PR+, HER2- breast cancer using standard protocol (adriamycin chemo to shrink tumor, lumpectomy, taxol chemo & radiation). I was just diagnosed with triple negative breast cancer in the same breast and will have to have a mastectomy. I’ve been reading Dr. Lee’s book about menopause. I’ve had all the menopausal symptoms since 2015 (weight gain of 25 lbs, dry vagina, low libido and raging hot flashes).. Only took Tamoxifen for 2 months and decided the benefits did not outweigh the risks, and it made me feel crappy. I just started taking black cohosh based on the recommendation of my gynecologist, but I’m wondering if low dose natural progesterone is safe for me to take? It looks like I could order this online and without a prescription, but I obviously don’t want to do anything to put myself at further risk. I did discuss this idea with the gyno office but they said I can’t do any natural hormones due to the breast cancer.
Hello,nice share.
Almost 20 years ago I was told I would never have children due to having endometriosis. My doctor suggested that I get my ovaries removed. After my diagnosis, I was contacted by my insurance company and told that they would cancel my insurance if I didn’t have my ovaries removed. I had to find a new insurance company and started researching everything I could find. I read Dr. Christine Northrup’s book, “Women’s Body Women’s Wisdom” and Dr. Lee’s book, “What Your Doctor May Not Tell You About Menopause”, and started taking bio-identical progesterone cream at that point – I wanted to have children. I have two wonderful and healthy children ages 13 and 18.
In 2016, my right ovary twisted due to a large tumor – I would not wish this upon my worst enemy! I had just had my annual gynecological exam and the doctor didn’t feel the 16cm tumor! I must add that I am thin – in fact some doctors consider me 10 lbs under weight. Fortunately that tumor was benign and yet I worried that I developed it because of taking the progesterone cream for so many years. Thus I immediately stopped taking the cream, as my doctors were never supportive of my taking it in the first place.
Approximately 20 months later the doctor found a lump in my left breast. Once again I did not allow the doctors to pressure me, I took time to research all of my options. I decided to start back on the progesterone cream. From October (when the lump was found) until June (8 months), when I had a lumpectomy, the lump hadn’t grow. Unfortunately the lump was IDC (ER+ and PR+) and the doctors insisted that I get radiation and take Tamoxifen – I have refused both.
It has now been 7 months since my surgery and I have had a series of blood tests and ultrasounds – no sign of re-occurrence. I would also like to note that I had a mammogram when I turned 40 (10 years ago) and from my research often wonder if this contributed to me getting breast cancer. I have dense breast and from what I have read mammograms are not effective for women with dense breasts. The breast cancer I had was found with an annual breast ultrasound. I have not had a mammogram for the last 10 years and never plan to get another one. When they found the lump in my breast, I refused the core biopsy because contrary to what doctors will tell you I believe these types of biopsies create tracks where the cancer can spread – not worth it. I insisted on going directly to the lumpectomy after researching and watching the lump for 8 months, I knew it was cancer.
So my point to all of this is After 20 years of research and experience, I believe bio-identical progesterone is healing and necessary for many of us. I got breast cancer when I stopped using it and the cancer stopped growing when I started using it again.
This is incorrect, you did not get breast cancer when you stopped taking it. Cancer develops on averages 5-10 yrs before it’s detectable on imaging or you feel a lump. I had an MRI when I was 35-no “detectable” breast cancer. I started taking bio-identical progesterone cream around this same time then at 40 I had another MRI and boom breast cancer. By the time a 1 cm BC tumor is discovered it started 8-10 yrs ago. So it started developing in my early 30’s it just was still small and at the cellular level that it hadn’t formed a discernible lump yet that imaging could pick it up. They only pick up a mass not things at the cellular level. Did my taking progesterone cream in the middle of my 30s help contribute to the formation of breast cancer (I was ER+ & PR+) or did it help to grow slowly, I don’t know, but I do know that your breast cancer had started to develop while you were on progesterone, It didn’t suddenly develop when you took a brief hiatus from the progesterone.
I was “estrogen dominant” for several years. After reading one of Dr John Lee’s book, I got a prescription for a BIO-IDENTICAL progesterone cream. Saved me!! Stay away from synthetics, but I encourage anyone that exhibits estrogen dominance to look at using BIO-IDENTICAL progesterone. I think we can avoid a lot of cancers by going this route. You don’t want estrogen dominance to remain un-checked.
Does this article apply to bioidentical hormone replacement?