Transition from hormone to chemotherapy

Even though my daughter's MBC was ER+, Lupron and Letrozole have not worked
for her.

Her onco has just started her on chemo with Xeloda plus Avastin as part of a
clinical trial.

The trial protocol requires her to go off Lupron - which worries my wife and
me even though the estrogen treatment has not worked.

I'd like to hear from anyone who has made the transition from hormone to
chemo and faced this issue - both from return of menstruation and efficacy
of treatment points of view.

Thanks
DB.