I've just started on Tamoxifen too. It can have positive side effects too. It has dampened my appetite it's made portion controll alot easier. So I've been loosing weight. A much needed thing. I haven't had any other side effects.
To me, I'm more concerned about developing cancer in my remaining breast than I do about a rarer cancer. From what I understand, the tamoxifen displaces the estrogen from any cancer cell, and hopefully starve them to death.
Kaybear