Biopsy is known (in the research literature) for a quite large number of false positive diagnoses. For this and other reasons the net benefit of masectomy is dismally low.

I sometimes wish doctors would understand a bit more about statistics and conditioned porbabilities and would care to tell their patients truthfully about risks involved and about the real amount of false positives. Sad thing, they often can't tell because they don't know. A German colleague sent a student to twenty doctors for a test. The "patient" asked each doctor after the (negative) test a few questions about what the result really meant (are there false negatives, how many, etc) . As far as I remember only one of the doctors showed an understanding of conditioned probabilities. All others gave wrong responses which could have misled a naive patient.

Wolfgang