Estrogen has several metabolites (break down products). Evidence is accumulating that certain metabolites are directly responsible for the initial genetic damage that can lead to cancer formation. Other metabolites actually protect against cancer.
16alpha-OH and 4-OH are the two main metabolites that have been associated with cancer formation. In contrast with 2-OH, a metabolite that appears to inhibit cell proliferation, and thus help stop cancer formation. Cancerous cells are simply cells that do not stop replicating.
A recent study of over 10,000 women found that pre menopausal women who developed breast cancer had a higher percentage of 16-OH than 2-OH estrogen metabolites. And, women who had more 2-OH metabolites had a 40% less likely chance of getting breast cancer.
Not all estrogen metabolites are created equal. The important take home message is that Estrogen is not evil, just certain estrogen metabolites are potentially cancer causing. The good thing is that you can help your body to metabolize towards the anti-cancer metabolites and create less of the cancer causing ones.
Decrease your pesticide exposure and keep a healthy weight. Increase your consumption of cruciferous vegetables (kale, broccoli, brussel sprouts, cabbage) and phyto-estrogen rich foods such as flaxseed. You can even take a supplement called DIM or I3C (concentration of cruciferous vegetables)
These are good tips for everyone, not just the women on bio-identical hormones.