Does Estrogen Really Cause Breast Cancer
The short answer? No, it does not! Mis-information and outdated studies are what guides many to believe that estrogen can raise the risk of breast cancer in women. The questions we should be asking are: what does new research tell us and what do we know now?
Lets talk about a recent book about womens health: Estrogen Matters: Why Taking Hormones in Menopause Can Improve Womens Well-Being and Lengthen Their LivesWithout Raising the Risk of Breast Cancer. The author is Avrum Bluming, an oncologist with more than 20 years of experience treating cancer.
Dr. Bluming has gone through the many years of research including clinical research at his own practice and hes come up with some important conclusions. The number 1 thing he has said is that estrogen does NOT cause breast cancer. I think many women are fearful of this, and therefore avoid the use of hormone replacement therapy.
He has also found that estrogen prevents heart disease. Heart disease or cardiovascular disease is a leading cause of death in women. I think its important that we understand the role of estrogen and preventing it and prolonging our lives.
where I discuss the importance of hormones in regard to heart disease.
Why Estrogen Does Not Cause Breast Cancer
Estrogen therapy is a vital part of hormone replacement for women in menopause and beyond. Unfortunately, conventional wisdom of the past has tied it negatively to breast cancer. With over 2 million breast cancer survivors in the U.S., there has been enormous debate surrounding using hormone replacement therapy during and after breast cancer treatment.
Should there be concern? Does estrogen actually cause breast cancer? What is the research telling us? Were here to answer these questions, debunk some myths, and find the truth.
Risk Factors You Can Change
Weight. Being overweight after menopause increases your odds.
Drinking alcohol.Alcohol is linked to breast cancer. Compared with nondrinkers, women who drink one alcoholic drink a day have a very small increase in risk, and those who are moderate drinkers have about a 20% higher risk.
Hormone replacement therapy . Long-term use of estrogen and progesterone increases the risk of breast cancer. This risk seems to go away if you’ve stopped using them for 5 years or longer.
Being inactive. Your odds go up if you donât exercise.
Reproductive history. Having your first child after age 30 or never having a full-term pregnancy puts you at higher risk. So does not breastfeeding.
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Estrone Estradiol And Estriol In Your Body
Estrogen dominance can lead to cancer in one of two ways: The first has to do with the concentration of each of the three different forms of estrogen–estrone, estradiol, and estriol–circulating within the body.
Estrone and estradiol both work within the body to increase expression of the BCL2 gene that causes cell development and growth, particularly in hormone-sensitive tissue such a breast or uterine lining. If unopposed, this cell proliferation can lead to cancer. In fact, nearly every risk factor for breast and uterine cancer can be either directly or indirectly linked to an increase in estrone, estradiol, or their receptor activity.
One such study in 2008 determined that high levels of estradiol were associated with a significantly higher incidence of breast cancer recurrence. In many cases of breast cancer, a gene known as the P53 tumor suppressor pathway is disrupted. The P53 gene is the opposing force for the BCL2 gene it causes natural cell death , and is responsible for balancing the effects of cell proliferation.
In a nutshell: estrone and estradiol stimulate the production of the BCL2 gene, while progesterone stimulates the production of the P53 gene. When the body is experiencing estrogen dominance, what it desperately needs is progesterone to counter the effects of cell proliferation. Some studies have demonstrated that, by stimulating the P53 gene, progesterone can affect apoptosis in cancer tumors.
Types Of Studies Of Hormone Therapy And Cancer Risk
Different types of studies can be used to look at cancer risk from menopausal hormone therapy .
Randomized controlled trials: In this kind of study, a group of patients get the drug being studied , and another group gets a placebo . Results from this kind of study are powerful because which group a patient is in is based on chance. This helps assure that the groups are similar in all ways, such as risk for cancer, except for the drug thats being studied. This is the best way to see the effects of a drug. These types of studies can also be double-blinded, which means neither the people in the study nor their doctors know which group they are in. This lowers the chance that thoughts or opinions about treatment could affect the study results. Unfortunately, these kinds of studies are costly, which limits the number of people in the study, how long the study can continue, and the number of studies done.
A major drawback of observational studies is that the people getting the treatment being studied may have different cancer risk factors than the people who arent. Plus, the treatment can differ between the people being studied. This makes it less clear that the differences seen are only due to the drug being studied and not other factors.
When observational studies and randomized controlled trials have different results, most experts give more weight to the results of the randomized controlled trial.
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Using Vaginal Estrogen Not Linked To High Breast Cancer Risk
An analysis of data collected as part of the Womens Health Initiative trial has found that postmenopausal women who use vaginal estrogen have the same risk of invasive breast cancer, stroke, blood clots, endometrial cancer, and colorectal cancer as women who dont use vaginal estrogen.
The research was published online on Aug. 14, 2017 by the journal Menopause. Read the abstract of Breast cancer, endometrial cancer, and cardiovascular events in participants who used vaginal estrogen in the Womens Health Initiative Observational Study.
The research is part of the very large Womens Health Initiative Observational Study, commonly called the WHI. Overall, the study includes information from more than 161,608 postmenopausal women who were ages 50 to 79 when they joined from 1993 to 1998. The WHI wants to find any links between health, diet, and lifestyle factors and health problems such as cancer.
For this study, the researchers looked at information from 45,663 women who were ages 50 to 79. The women had not taken any type of hormone replacement therapy. Information about vaginal estrogen use was self-reported in the regular questionnaires sent out as part of the WHI. Information about the specific dose or type of vaginal estrogen — ring, cream, or tablet, for example — wasnt reported.
For women who still had their uterus and used vaginal estrogen, the risk of:
- blood clots
Signs Of Breast Cancer
Take time to get to know the normal look and feel of your breasts while showering, dressing or looking in the mirror so you can detect any changes that may indicate cancer such as:
- A lump, lumpiness or thickening.
- Changes to the nipple such as a change in shape, crusting, a sore or an ulcer, redness or a nipple that turns in when it used to stick out.
- Changes to the skin of the breast such as dimpling of the skin, unusual redness or other color changes.
- Change in the shape or size of the breast either an increase or decrease.
- Unusual discharge from the nipple without squeezing.
- Swelling or discomfort in the armpit.
- Persistent, unusual pain not related to your normal monthly cycle, which remains after a menstrual period and occurs in one breast only.
Though not necessarily cancer, these signs should be checked by your doctor without delay.
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Risks For Breast Cancer
A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes breast cancer develops in women who dont have any of the risk factors described below.
Most breast cancers occur in women. The main reason women develop breast cancer is because their breast cells are exposed to the female hormones estrogen and progesterone. These hormones, especially estrogen, are linked with breast cancer and encourage the growth of some breast cancers.
Breast cancer is more common in high-income, developed countries such as Canada, the United States and some European countries. The risk of developing breast cancer increases with age. Breast cancer mostly occurs in women between 50 and 69 years of age.
Effect Of Castration On Tumor Development In Erko/wnt
As exogenous E2 increased tumor incidence and reduced latency, we reasoned that castration, by lowering endogenous E2, should also reduce tumor incidence from levels observed in intact ERKO/Wnt-1 animals. For these experiments, we compared intact and castrate ERKO/Wnt-1 animals. Castration delayed tumor onset from 12 to 23 months and reduced tumor incidence from 80% to 50% . Our working hypothesis is that both ER dependent and ER independent effects of estradiol are involved in carcinogenesis. This experiment also allowed verification of the expected ER dependent effect on the process of carcinogenesis. Tumors developed sooner in the ER+/+/Wnt-1 animals than in those lacking ER .
Since castration reduced tumor incidence in the intact ERKO animals, we reasoned that pharmacologic suppression of estrogen production should also exert similar effects. We had previously developed a regimen sufficient to block ovarian estrogen production to castrate levels in rodents with high-dose letrozole administration. Letrozole, given at a dosage of 20 lg/day for 5 days a week, increased 50% tumor incidence time from 12 to 18 months . The effect of letrozole was dose-dependent, since no difference in 50% incidence time point or overall incidence was observed in animals receiving a lower dose of AI versus vehicle .
Postmenopausal Estrogen And Risk Of Breast Cancer: What Is The Real Story
I am responding to an article in the January 25, 2020, issue of The ASCO Poston the conclusion of the 19-year follow-up on the Womens Health Initiative presented by Rowan T. Chlebowski, MD, PhD, at the 2019 San Antonio Breast Cancer Symposium: Postmenopausal estrogen administration does not increase the risk of breast cancer after all, he said, and, in fact, it may decrease the risk the real culprit is estrogen combined with progesterone. Given that the WHI was largely responsible for frightening millions of women and their physicians into believing that estrogen causes breast cancera conclusion that it has been modifying and retracting over the past decadeit behooves us to try to understand what is really going on.
The current WHI update report that postmenopausal estrogen does not increase the risk of breast cancer is reinforced by other long-established findings in the medical literature, such as the 70% decrease in breast cancer risk associated with a full-term pregnancy before the age of 18 the lack of benefit resulting from an abortion at the time of breast cancer diagnosis and the safety of pregnancy after treatment of breast cancer, even among estrogen receptorpositive women.
This remarkable analysis should have been incorporated into the 19-year interpretation of the results presented in San Antonio and published in The ASCO Post article.
Avrum Bluming, MD
Emeritus Clinical Professor of Medicine
Lowering Estrogen Levels From The Ovaries
This type of treatment only works in premenopausal women who have functioning ovaries. It can help some types of hormone therapy work better. It is also used to treat cancer that has spread.
There are three ways to lower estrogen levels from the ovaries:
- Surgery to remove the ovaries
- Radiation to damage the ovaries so they no longer function, which is permanent
- Drugs such as goserelin and leuprolide that temporarily stop the ovaries from making estrogen
Any of these methods will put a woman into menopause. This causes symptoms of menopause:
- Hot flashes
- Loss of interest in sex
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Possible Side Effects Of Ais
The most common side effects of AIs are:
- Hot flashes
- Bone and joint pain
- Muscle pain
AIs tend to have side effects different from tamoxifen. They don’t cause uterine cancers and very rarely cause blood clots. They can, however, cause muscle pain and joint stiffness and/or pain. The joint pain may be similar to a feeling of having arthritis in many different joints at one time. Options for treating this side effect include, stopping the AI and then switching to a different AI, taking a medicine called duloxetine , or routine exercise with nonsteroidal anti-inflammatory drugs . But the muscle and joint pain has led some women to stop treatment. If this happens, most doctors recommend using tamoxifen to complete 5 to 10 years of hormone treatment.
Because AIs drastically lower the estrogen level in women after menopause, they can also cause bone thinning, sometimes leading to osteoporosis and even fractures. If you are taking an AI, your bone density may be tested regularly and you may also be given bisphosphonates or denosumab , to strengthen your bones.
Study Uncovers Why Hormones Increase Breast Cancer Risk
EAST LANSING, Mich. Researchers have identified how the hormones progesterone and estrogen interact to increase cell growth in normal mammary cells and mammary cancers, a novel finding that may explain why postmenopausal women receiving hormone replacement therapy with estrogen plus progestin are at increased risk of breast cancer.
The discovery that both estrogen and progesterone must be present for the increased production of the protein amphiregulin, which binds to mammary cells and promotes cell growth, could lead to new treatment methods for the disease, said Sandra Haslam, director of Michigan State University’s Breast Cancer and the Environment Research Center and lead researcher on the project.
The study, funded by the Department of Defense’s Breast Cancer Research Program and published in Hormones and Cancer, looked at why progesterone combined with estrogen may contribute to increased breast cancer risk. In the study, researchers used both the native hormone, progesterone, and a synthetic compound, progestin – obtaining the same results.
The finding might help explain earlier results from the groundbreaking Women’s Health Initiative showing the risk of breast cancer is significantly greater for postmenopausal women who received hormone replacement therapy with combined estrogen plus progestin compared to women receiving estrogen alone.
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Estrogen Linked To Bone Health
A healthy level of estrogen in your body builds and maintains strong bones. However, if you’ve had chemotherapy or if you’re taking estrogen-suppression medication after treatment for breast cancer, your estrogen levels will be low. Guard your bone health by understanding how estrogen affects your bones.
What Is A Hormone Receptor
In breast cancer, hormone receptors are the proteins located in and around breast cells. These receptors signal cells both healthy and cancerous to grow. In the case of breast cancer, the hormone receptors tell the cancer cells to grow uncontrollably, and a tumor results.
Hormone receptors can interact with estrogen or progesterone. Estrogen receptors are the most common. This is why ER-positive is the most common form of breast cancer.
Some people are diagnosed with progesterone receptor-positive breast cancer. The key difference is whether cancerous cells are getting growth signals from estrogen or progesterone.
Testing for hormone receptors is important in treating breast cancer. In some cases, there are no hormone receptors present, so hormone therapy isnt a good treatment option. This is called hormone receptor-negative breast cancer.
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Hormone Therapy For Breast Cancer
Some types of breast cancer are affected by hormones, like estrogen and progesterone. The breast cancer cells have receptors that attach to estrogen and progesterone, which helps them grow. Treatments that stop these hormones from attaching to these receptors are called hormone or endocrine therapy.
Hormone therapy can reach cancer cells almost anywhere in the body and not just in the breast. It’s recommended for women with tumors that are hormone receptor-positive. It does not help women whose tumors don’t have hormone receptors .
Age At Menarche Is More Influential Than Age At Menopause On Breast Cancer Risk
The observation that lengthening the reproductive life of a woman, either by an earlier menarche or later menopause, increases the risk of breast cancer would suggest that the overall duration of the exposure to estrogen is underlying the risk. However, a recent meta-analysis of reproductive events and breast cancer risk has found that age at menarche may be more of a deciding factor on the risk than age at menopause .
These findings contradict earlier theories that the influence of age at menarche and menopause on breast cancer risk was simply due to the duration of exposure to cycling ovarian hormones. Instead, it seems that the timing of the first exposure of the mammary gland to cyclic hormones sets up a developmental program that has consequences for breast cancer risk later in life.
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Controlling Estrogen Level To Combat Breast Cancer
Regardless of exactly how estrogen causes increased breast cancer risk, it is worth keeping low estrogen levels in your body because this is shown to potentially reduce your breast cancer risk and is an excellent natural remedy for hormone-receptor-positive breast cancers that do arise.
- Stop smoking
- Reduce saturated and trans fats
- Reduce usage or eliminate hormone replacent therapy during and after menopauseThe end of a womans menstrual cycles, defined as 12 consecutive months of no menstrual periods.
- Choose to breastfeed, if possible
All of the above factors contribute to reducing estrogen levels in the body. Controlling them helps decrease your risk for breast cancer and gives you a healthier lifestyle in general.
Of course, there are also a number of factors relating to estrogen which cannot be controlled. Women who start their period early or begin the menopause late are believed at higher risk of developing breast cancer, for example. So are those who have children late or dont have any at all. This is possibly because these women are exposed to more estrogen overall in their lifetimes. On the flipside, each time you get pregnant for a prolonged period, you effectively decrease the number of menstrual cycles and hormone fluctuations in your lifespan, reducing the breast cancer risk.