Can estrogen cause breast cancer? I am asking because my moms sister my aunt just found out she has breast cancer and they said she had a very high estrogen level in her body? I am concerned because I have had breast pain issues for years they have never found lumps some density last year but they said it looked normal. I have another mammo next month. I am 38 and am wondering if I should still continue to take the pill. In the past it caused me breat pain as it is now, but I had to go back on it to regulate my periods, I am just wondering since I am at higher risk to get breast cancer due to my aunt and my grandmother if I should condinte to take the pill due to the estrogen?