I, too, had invasive ductal carcinoma, stage 1. I started with 5 mg., then 10, then 10.5. At 10.5 I started bleeding. Imagine having post menopause bleeding, coupled with hot flashes! I went down to 10mg. and dealt with leg pain and swelling, hair thinning and loss, hot flashes, mood swings, and brain fog. I went down to 5mg. and it is so much better. But, I didn't stop there. I take indole-3-carbinol. 200mg. It is being investigated as a more natural way to deal with ER PR positive breast cancer. It acts as an aromatase inhibitor. The trial is using 150mg. X 2. It is the only way I can try to do something, and not give up completely. I won't live with the quality of my life being so ruined by the utter crap the oncologist offer.