Up to half of all women with breast cancer could benefit from taking progesterone, according to a study published last July in the journal Nature. The paper outlined how progesterone, but not the progesterone-like molecules used in the Pill, Prempro, and the Merena IUD, turns estrogen into an anti-cancer hormone in estrogen and progesterone receptor positive tumors.
It has long been known that breast cancers with both estrogen and progesterone receptors have the best clinical outcome, but the reason remained unknown. It is also well known that when estrogen binds to the estrogen receptor, genes promoting tumor growth are switched on. However, the role of the progesterone receptor was unclear. This study has found that when progesterone binds to the progesterone receptor, it reprograms the action of the estrogen receptor to promote cell death and the development of normal cells, reducing the size of the tumor.
Of course, the press focused on the potential of progesterone to offer a safe, inexpensive, side effect-free way to treat common breast cancers. However, most breast cancers take 6 - 8 years before they are detectable on mammogram. Additionally, progesterone naturally declines with age and also with stress. I assert that progesterone would provide an inexpensive, safe and side-effect free way to prevent breast cancer, and failure to recognize and treat low progesterone may be behind the ever increasing rates of breast cancer. Women could easily be screened for symptoms of low progesterone such as PMS, heavy periods, postpartum depression, insomnia and multiple miscarriages and prescribed on progesterone therapy.
Of course doctors would need to learn to prescribe bio-identical progesterone, as they don’t receive this training in medical school or residency, and most mistakenly think the progesterone-like compounds in the Pill, Prempro and the Merena IUD are the same as bio-identical progesterone. These progesterone-like compounds do not reprogram the estrogen receptor and may actually increase the risk of breast cancer.