hormone therapy for HER2

There were studies I remember from back when I was dx four years ago, that said AI's worked better for her2 ER+ tumors, then Tamoxifen-- however, if you're pre meno, it's not like you have that option.

Juniper yes- you have a point-- but at least for me, inducing menopause before I was even 30, and having not yet had kids just wasn't an option...

it may be for others though.

I'm pre-meno like Beth so Tamox is my only option.  I've been in chemo pause though and I'll have my levels checked the end of the year.  May switch to AI but Tamox is so easy for me to tolerate.

My onc at Mayo Clinic has done research showing that responce to tamoxifen depends on your specific gene type.  Those that are extemsive metabolizers or tamoxifen have good response, even HER2+ (most of the population are extensive metabolizers), those that are poor metabolizers have extremely poor response - even tumor growth fueled by tamoxifen.  About 6-7% or the population are poor metabolizers of tamoxifen.  There are also intermediate metabolizers. 

There is a simple blood test that will tell you if you are a extensive metabolizer, imtermediate or poor metabolizer.  Look for a test for the CYP2D6 enzyme.  

I suggest googling Dr. Mathew Goetz.  He has published several articles on this.  The test is only a few hundred dollars and could save your life.

Bottom line is you should be on tami if you are extensive metabolizer, and be on AI with ovarian ablation (if premenopausal) if a poor or intermediate metabolizer. 

 This test is available commerically.  I would insist your onc order it for you. 

Good Luck