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Breast Cancer Chemoprevention

Breast cancer chemoprevention may have a place in preventing breast cancer, but bioidentical hormone replacement as discussed below may even be more effective; zinc is also a breast cancer preventative.


In this case physicians prescribed the anti-estrogen medication tamoxifen to a group of women who have a familial constellation for breast cancer of both breasts. Notably, this reduced the risk of developing breast cancer in the other breast after mastectomy (surgical removal of the one breast). In essence there was a risk reduction of breast cancer in the other breast of 40% of the expected risk with this medication.

However, tamoxifen has significant side effects and the use of it has limitations to high-risk settings. Certainly, the idea of cancer prevention utilizing hormone modulating medications is not new. In males there is an equivalent prostate cancer prevention medication, finasteride. Physicians use it to treat an enlarged prostate gland. It must be remembered that in males finasteride also has a significant prostate cancer prevention effect. It is even effective at low doses (the same doses as the physician uses for male baldness treatment).

Breast cancer prevention with bioidentical hormones

This makes it more likely that in women there would also be a useful place in certain instances for chemoprevention of breast cancer. However, a new observation is that women on balanced hormone replacement with bio-identical estrogen and progesterone hormones enjoy longer lives with no development of breast, uterine, colon and other cancers. Researchers published these facts in the anti-aging literature between 2000 and 2008. Dr. Lee points out that with saliva hormone tests, which is the only reliable test that reflects the tissue levels of hormones, estrogen levels can be kept at a ratio of 1:200 (level of progesterone 200-fold higher or more than the estrogen level). This will keep the carcinogenic effect of estrogen under control and prevent the development of breast cancer or uterine cancer (Ref. 9 and 10).

Other agents of interest

Other agents of interest are retinoids (=vitamin A derivatives), which have been very effective in animal experiments and are being investigated for effectiveness in humans. The aromatase inhibitor, astrozole (brand name: Arimidex), prevents the conversion of androgens from the adrenal glands being converted into estrogen substances.

This will reduce the risk for breast cancer for those cancers that have positive estrogen receptors even further. Your doctor or oncologist can advise you what medication applies to your condition.

It appears that now this type of approach is much more restricted. Perhaps it is still warranted in families where there is a genetically higher risk of breast cancer, but not the high risk setting that warrants bilateral removal of the breast tissue. There has to be a balance between the breast cancer risk reduction of Tamoxifen and the fact that endometrial cancer (=uterine cancer) is more common on it. Discuss this with your family doctor.

Breast cancer chemoprevention (Bioidentical Hormone Cream)

Breast cancer chemoprevention (Bioidentical Hormone Cream)

Bio-identical hormone replacement

By all means, a more logical prevention of breast cancer is to go on a DASH diet, which contains a lot of fruit and vegetables (diet originally developed for patients with high blood pressure). In addition, hormone replacement with bio-identical hormones are useful as indicated above. The first thing to remember is that the doctor starts bioidentical hormone replacement with bio-identical progesterone hormone before estrogen replacement. This saturates the progesterone receptors and also partially the estrogen receptors in breast tissue, the uterus and the ovaries.

Do estrogen replacement cautiously with low doses of bioidentical estrogen

If estrogen levels are low, a small amount of estrogen cream can be added (Bi-Est cream) next. However, the physician  monitors the hormone levels and keeps the estrogen/progesterone ratio at 1:200 (level of progesterone 200-fold higher or more than the estrogen level) or higher to avoid any risk of cancer development. Ref. 9 gives details about this approach, but I have read many other articles and books that have confirmed this as well.

Hormone receptors

In general, this makes biological sense: it all has to do with the fact that women are born with a certain set of hormone receptors. To clarify, between puberty and up to the age of 30 the hormones glands produce enough hormones. With attention to the hormone receptors throughout all the major organs (including heart, brain, muscles, bones) have enough hormones to stimulate them.  In return this allows the woman to have low cancer rates and low cardiovascular risks. Sooner or later melatonin and human growth hormone are slowly, but steadily produced less every year beyond the age of 30. When menopause approaches, progesterone secretion is lower.  In fact, missing ovulations reduce progesterone production in the ovaries.


With this in mind, at the time of the last period, when the physician tells a woman that she is in menopause, both estrogen and progesterone decline steeply, but progesterone at a much greater rate. As an illustration, the end result is often that the estrogen/progesterone ratio is less than 1:200. Certainly, this means that the woman is estrogen dominant. It is important to realize that too much estradiol in the system puts the woman at a higher risk for developing breast cancer, uterine cancer, ovarian cancer and colon cancer. However, when the hormone abnormalities are remedied, and the estrogen/progesterone ratio is normalized (1:200 or higher) the woman feels better.

Rebalanced hormone receptors

For one thing, she has more energy, sleeps better and the risk for cancer is back to being low as it was when she was less than 30 years old. In short, the reason for this is that the hormone receptors are balanced again and the organs function normally.

Hypothyroidism can complicate breast cancer prevention

A point often overlooked is that the thyroid gland is starting to malfunction (hypothyroidism is setting in) as well, something your doctor may also have to address. To repeat, please understand that all your hormone replacements must be with bio-identical hormones from a compounding pharmacy. This will ensure that the hormone fits the hormone receptor, which is what the body cells need.

Zinc prevents breast cancer

With attention to zinc, understand that it is a trace mineral that has many functions in the body, one of them is the repair of breaks in the DNA. This has lead to research showing that several cancers are prevented by zinc supplements (30 to 50 mg  per day). See more details here:

Breast cancer patients benefit from vitamin D3

In March 2014 a study was published that was the result of a meta-analysis of 5 observational studies (Ref. 10). 4443 women were part of this meta-analysis and a total of 471 cases of breast cancer were reported. When the vitamin D3 blood level (25-hydroxyvitamin D) was measured and patients were classified into high and low vitamin D3 levels an interesting result was found: those women whose level was 30 nanograms per ml or higher had a reduction in mortality from breast cancer of 44% when compared to the low group, which was 17 or less nanograms per ml. Many other studies have recommended that a vitamin D3 level of 50 to 80 ng/ml is the ideal level for cancer prevention. There is a related study by the same author:


The following references were used apart from my own clinical experience:

1. Cancer: Principles &Practice of Oncology, 4th edition, by V.T. De Vita,Jr.,et. al J.B. LippincottCo.,Philadelphia, 1993.Vol.2: Chapter 48.

2. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 177.

3. Cancer: Principles&Practice of Oncology. 5th edition, volume 1. Edited by Vincent T.     DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter 36: 1541-1616.

4. BS Herbert et al. Breast Cancer Res 2001;3(3):146-149.

5. BS Herbert et al. J Natl Cancer Inst 2001 Jan 3;93(1):39-45.

6. Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier

7. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc

8. Dr. John R. Lee and Virginia Hopkins: “Hormone Balance Made Simple – The Essential How-to Guide to Symptoms, Dosage, Timing, and More”. Wellness Central, NY, 2006

9. Dr. John R. Lee, David Zava and Virginia Hopkins: “What your doctor may not tell you about breast cancer – How hormone balance can help save your life”, Wellness Central, Hachette Book Group USA, 2005. Page 29 – 38 (Chapter 2): Risk factors for breast cancer. Page 360 to 374 explains about xenohormones and how they cause estrogen dominance. Pages 221 to 234 (chapter 12) explains why Tamoxifen is less effective and bio-identical progesterone is more powerful in preventing breast and uterine cancer.

10. Dr. Garland: Anticancer Research 2014, March; 34(3):1163-1166.

Last modified: August 15, 2019

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.