Estrogen alone is not the issue when it comes to increasing the risk of breast cancer. The real issue is how is your estrogen being metabolized. You want to have your doctor order a test that evaluates the estrogen metabolites. The Dutch Test (https://dutchtest.com) or the Rhein Hormone Test (http://www.rheinlabs.com)
The liver converts estrogens into estrogen metabolites. Three of estrogen’s metabolites, the breakdown products of this hormone, are 2-hydroxyestrone, 4-hydroxyestrone, and 16-alpha-hydroxyestrone.
Since the 1980s, 2-hydroxyestrone has been considered a “good” or chemoprotective form of estrogen, while 16-alpha-hydroxyestrone has been associated with the development of cancer. It can fuel the growth and division of hormone-dependent and other cancer cells more than the 2-hydroxyestrones can. The 2-hydroxyestrones, in contrast, have almost no estrogenic effect. Prevailing evidence has shown that the ratio of 2-hydroxyestrone to 16-alpha-hydroxyestrone is relevant as a risk factor for estrogen-sensitive cancers, including breast and cervical cancers. Simply put, when it comes to estrogen metabolites, you want more 2s than 16s. And guess what can help the body do that? Cruciferous vegetables.
Two components in cruciferous vegetables are indole-3-carbinol (I3C) and diindolylmethane (DIM). Studies have found that these compounds can inhibit the formation of the “bad” 16-alpha-hydroxyestrone estrogen metabolite. One study found that DIM had the ability to decrease its production by 50 percent while increasing production of the “good” 2-hydroxyestrone metabolite by 75 percent.
I3C is found in a number of cruciferous vegetables, including broccoli, brussels sprouts, cabbage, cauliflower, collard greens, kale, kohlrabi, mustard greens, radish, rutabaga, and turnip. The highest concentrations are found in garden cress (different from watercress) and mustard greens.
Winters Nasha, Kelley Jess, The Metabolic Approach to Cancer, Chelsea Green Publishing, 2017
Michelle Whirl-Carrillo, Ellen M. McDonagh, J. M. Hebert, H Chun Gong, K. Sangkuhl, C. F. Thorn, Russ B. Altman, and T. E. Klein, “Pharmacogenomics Knowledge for Personalized Medicine,” Clinical Pharmacology and Therapeutics 92, no. 4 (October 2012): 414-17
Heather Greenlee, Yu Chen, Geoffrey C. Kabat, Qiao Wang, Muhammad G. Kibriya, Irina Gurvich, Daniel W Sepkovic, et al., “Variants in Estrogen Metabolism and Biosynthesis Genes and Urinary Estrogen Metabolites in Women with a Family History of Breast Cancer,” Breast Cancer Research and Treatment 102, no. 1 (March 2007): 111-17