Progesterone and Cancer

Dr. Weeks’ Comment: For the past 30 years, I have championed the controversial therapeutic recommendation that when a woman with breast cancer’s receptor status comes back “ER + and PR+” – meaning there are receptors in the breast cancer both for estrogen and for progesterone – that the clinical strategy should be to stop estrogen which fuels cancer but to actually give bioidentical progesterone because progesterone offers three powerful anti-cancer actions: 1) anti-estrogen 2) lowers blood sugar and 3) lowers adrenalin (stress and oxidation). This is a minority position since most doctors tell the patient to stop both estrogen and progesterone. Further, we endorse a topical bio-identical progesterone cream on the site of the cancer because, topical progesterone is best absorbed (avoiding “first pass metabolism and degradation in the liver).

Happily, the tide is turning and more to my opinion as people understand that most doctors have been duped: pharmaceutical companies want everyone to think that their synthetic, near-miss, knock-offs like “Hydroxyprogesterone” and “Progestin” and “Progestogen” are identical to natural bioidentical progesterone. They are NOT identical to progesterone. A half truth is worse than a lie. Here are the warnings for using hydroxyprogesterone:

“Makena should not be used if you:

  • Have now or have had a history of blood clots or other blood clotting problems
  • Have now or have had a history of breast cancer or other hormone-sensitive cancers
  • Have unusual vaginal bleeding not related to your current pregnancy
  • Have yellowing of skin due to liver problems during your pregnancy
  • Have liver problems, including liver tumors
  • Have uncontrolled high blood pressure

Before you receive Makena, tell your healthcare provider if you:

  • Have an allergy to hydroxyprogesterone caproate, castor oil, or any of the other ingredients in Makena
  • Have diabetes or prediabetes
  • Have epilepsy
  • Have migraine headaches
  • Have asthma
  • Have heart problems
  • Have kidney problems
  • Have depression
  • Have high blood pressure”

Don’t fool with Mother Nature. “Hydroxyprogesterone” and Progestin” and “Progestogen” ,while intentionally hard to distinguish linguistically from the real hormone, are indeed toxic and must be avoided. Here following is an excellent article supporting my clinical position. See also this LINK about the beneficial role of progesterone and cancer.

Altern Ther Health Med.
 2017 Nov;23(6):24-32.

In Defense of Progesterone: A Review of the Literature.

Lieberman ACurtis L.


Context • The medical literature on the use of progesterone in postmenopausal women is often confusing and contradictory. Some physicians implicate natural progesterone in an increase in the risk of breast cancer. The chemical structure of natural progesterone (P4) is quite different from chemically altered, synthetic chemicals called progestins, which results in different actions at the cell level. 

Objective • The research team intended to review the literature to examine the benefits and safety of natural progesterone and determine whether it can cause an increase or decrease in breast cancer risk.

 Design • A review of the medical literature to examine the benefits and safety of natural progesterone as compared with synthetic progestins. 

Intervention • Studies examined compared controls not receiving hormone therapywith women receiving estrogen alone and in combination with natural progesterone and with various synthetic progestins, such as medroxyprogesterone acetate-the most commonly used synthetic progestin.

 Outcome Measures • Outcome measures included factors such as progression and survival of breast and other cancers and other epidemiological and laboratory data. 

Results • A meta-analysis of 3 studies involving 86 881 postmenopausal women reported that the use of natural progesterone was associated with a significantly lower risk of breast cancer compared with synthetic progestins. 

Anovulation and low levels of serum progesterone have been associated with a significantly higher risk of breast cancer in premenopausal women. Use of progesterone has been linked to lower rates of uterine and colon cancers and may also be useful in treating other cancers such as ovarian, melanoma, mesothelioma, and prostate. 

Progesterone may also be helpful in preventing cardiovascular disease and preventing and treating neurodegenerative conditions such a stroke and traumatic brain injury. 

Conclusions • Physicians should have no hesitation prescribing natural progesterone. The evidence is clear that progesterone does not cause breast cancer. Indeed, progesterone is protective and preventative of breast cancer.

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