The research is quite confusing and controversial on this topic, there are reports that suggest that even natural hormones may increase proliferation of breast cells so at this point of knowledge I usually do not recommend the bioidentical hormones to women with breast cancer. There are a great deal of other effective options to consider for the treatment of hot flushes associated with Tamoxifen such as acupuncture, exercise , meditation, black cohosh (refer to previous question) and there are a few studies that might suggest even homeopathic remedies

Moshe Frenkel, M.D.