Why I do not recommend progesterone cream to patients using estrogen

We have studies clearly indicating the protective effect of oral progesterone when it comes to endometrial cancer (The PEPI trial). We also have some smaller studies on vaginal progesterone achieving the same effect where one of them was actually done in Falun, Sweden.

As far as I know, we do not have a double blind study indicating the protective endometrial effect of transdermal progesterone.

As you know, I do recommend progesterone cream to all of my PMS and perimenopausal patients  unless the more sedating effect of oral progesterone is required. I would gladly prescribe the progesterone cream to all my menopause patients the day we have access to such a study. It is well known that unopposed estrogen increases the risk of endometrial cancer five-­‐fold while adding the oral progesterone will lower that risk to a point were the risk is even lower than when not taking any hormones at all.

Several resellers of progesterone cream in Sweden claim that there are studies on progesterone cream and its protective effects when it comes to breast cancer. They refer to a small study called the Chang Study.

The Chang study was a very small study of forty premenopausal women undergoing breast surgery for the removal of a lump. They looked at plasma and breast tissue concentrations of estradiol and progesterone.

Although I believe that progesterone is vital in the protection of both breast and endometrial cancer, this particular study does not in any way prove that progesterone cream protect women against breast or especially endometrial cancer. What they found in this study, is that increased estradiol concentration in blood and breast cells increases the number of cycling epithelial cells. Increased progesterone concentration in plasma and breast cells significantly decreases the number of cycling epithelial cells and concluded that exposure to bioidentical progesterone gel for 10 to 13 days reduces estradiol-­‐inducedproliferationofnormalbreastepithelialcellsinvivo. They are talking about increased proliferation and that does not mean cancer. It is what estrogen does to both breast tissue and endometrial tissue, while progesterone reduces such proliferation. This is the natural cycle of life. Estrogen stimulates female tissue and progesterone stops that stimulation. That is how the uterus is getting ready for an egg to implant every menstrual cycle during our fertile  lives. Again, this does not in any way prove the protective effect on the endometrium.

As my goal in treating women is to help them feel better, be healthier while causing no harm I will continue to recommend treatment protocols backed up by science.


Mia Lundin