Did you have G-CSF with or prior to the navelbine?
It's anecdotal but..
Mom went on a unique weekly/metronomic Zometa schedule upon having PET/CT and neck MRI suggesting bone met. It
appears to be gone or inactive at this point. There were a bunch of other meds and supplements happening too, so hard to know for sure what did the trick. It was done also based on the idea that Zometa can fight cancer in tissues as well. Just a thought. If you could get Herceptin weekly too, might give some synergy and reduce potential heart damage from extended Herceptin. Regarding the biopsy, the questions seem to be whether the images could be anything else and if it is cancer, how would treatment be changed by the biopsy.
I imagine Chelee has looked at bone mets and biopsy options inside out and will chime in.
More on bone mets
here
(if you have a treatment history signature, folks can give you better feedback)