Dear Ros Escott:
   I went through the very same situation you asked about!!  (I am LLL
Leader.)   My surgeon and  obstetrician with specialty in oncology said I
needed to wean my 7 month old before the stereotatic biopsy for the reason
you mentioned They said that a fistula could form from the biopsy if I was
still lactating. A fistula is a (nasty) abnormal passage within body tissue
that collects fluids or whatever's around, i.e. bm.  When fluids collect in
the body and sit, the bacteria etc. multiply then you have an infection!  I
also talked with LLL Professional Liason Department in Texas, who referred me
to a breast Oncologist with extensive knowledge of bf.  You might want to
contact LLLI for their more current information as my situation happened 17
months ago.  Since my mom had died the week before from metastatic breast
cancer, every MD in West Texas was very anxious for me to get a biopsy.  So
with the LLL information, physicians info , etc., I weaned my baby to formula
(*&%@@$#!!)   Then I relactated with an SNS.  Yes!  Now she'll be 2 soon and
is happily nursing away still! YEA!  Anything I missed?  Let me know how the
mom does if you have a chance.  Cindy Lundberg