Halo Breast Pap

Fifteen years ago or so, I had a procedure called 'ductal lavage' that was similar to what you describe. A small catheter was inserted through a milk duct to retrieve fluid, which was sent to pathology.  At the time, I asked the surgeon doing the procedure (which was painless requiring no pain protection) how the procedure was helpful, since the breast has multiple ducts and she was sampling from just one duct in each breast. Unbelievably, my question surprised her, and she did not have an answer except to say 'gee, that's a very good question.'  My path was negative but it really did not give me much peace of mind, because of the limits of what was sampled--precious little.  The ductal lavage procedure seemed to disappear not long after I had it, so I'm surprised to hear of it here.  I've not heard of it by the new name, but I would want to know whether it samples fluid from just one random duct, or more comprehensively.  If you learn more, I'll be interested in hearing about it, especially for my daughter's info, as we have a ridiculous family history of BC.