Hello! I have a Radial Scar and you are right - they are very confusing and there is very little information out there!
I was diagnosed in 2018 after it was picked up on my first routine mammogram. They present just like a cancer on mammograms.
I was called back to the clinic, had a needle biospy and as you have mentioned - I then had a vacuum biopsy. The vacuum biopsy takes samples from across the scar - like a 'cross hatch' - so tested all areas for any cancer. It all came back benign.
In my case (which is unusual I believe) they decided to leave the Radial Scar in place. Perhaps because mine is 10cm diameter!! I'm still not sure if this is the best decision, because as you say - it is as yet unknown in terms of research (they are apparantly quite rare things) if they can have cells which can turn into pre-cancerous cells, or they can 'mask' real cancers on mammograms.
I was told that all I needed to do was go back to having 3 yearly mammograms. That felt wrong to me. They shook my life up, told me it was a 50% chance of having cancer out of the blue, and then when benign just sort of thre me out of the other end of the system. The Breast Cancer screening units are amazing and the turn aound is very fast in a 'one stop shop'- but for those of us who have something there but not cancer there is no after support / information.
I decided to take it upon myself to pay for a mammogram every 12 months privately so as to 'keep an eye' on things. At some point I may see a specialist privately and ask their opinion as, as you mention, most people witll be operated on to remove it. I'm very aware that mine is still there.
If they recommend a vacuum biospy I can tell you about that. It sounds scary but it was really fine. All done with local anaesthetic. If youbhave any questions I'll do my best to answer - but over 3 years of searching on the web for further information and I still don't know much more!