Abnormal mammogram and breastfeeding
I had a biopsy done when my son was still a smidge, fully breastfed at about 7 months. I was actually breastfeeding him on the other side during the ultrasounds, and he was there for the biopsy too. (not feeding though!)
You don't need to stop - they probably just say things like that in ignorance. Always keep in mind people will just say stuff like that. I imagine it might be more uncomfortable with a load of milk, but feeding off beforehand would cancel that out. Perhaps that is what they mean. What could happen? Milk squirts, lol.
The biopsy - I was so worried, but it was a piece of cake - the needle was small I barely even felt anything AT ALL!
Turned out to be a fat blob, which is very common in these circumstances, I've since met many mothers who had the same thing. Hoping the same for you.