Research on hormone treatment used with Herceptin

Can anyone point me to clinical studies that show hormone treatments such as Tamoxifan or Faslodex are NOT synergistic with Herceptin? Several of the oncs we've consulted for my mom have said that hormone treatments work counter to Herceptin, since the hormone treatment slows down the cancer, and Herceptin targets fast growing cells.

However, my mom's new onc wants her to go on Faslodex/Herceptin, which I know many people have used with great success. I've found research that says hormone treatments ARE synergistic with Herceptin, but I was wondering if there had been studies that say the opposite, or if the oncs have just been offering their theories.

I even consulted Johns Hopkins University, and they said oncs in general are split in opinion on this, and the decision was really up to us. So I wanted to have as much literature on both sides as possible so we can make a decision.

Thanks in advance!

Stephanie, mom to Marie