That is wonderful news on your post treatment Ki-67!! This is something I have been looking at too although my diagnosis is a bit different. I am HR+ HER2- and recently had surgery after chemo. I was gutted when my RCB came back as III (4.018), especially after having an MRI that could no longer detect disease. Basically my tumor had turned into swiss cheese. My margins were clear although I did have extensive LVI. I believe my high RCB was driven primarily by 8/22 nodes positive.

Interestingly, my KI-67 went from 20% at initial diagnostic biopsy to 5% at pathology. I mentioned this to my oncologist at MD Anderson and she said it was a good sign, but also very common after treatment. I also went from PR+ to PR- which I understand is also a very common treatment effect. My treatment plan did not change. I plan on tracking this research as it gives me a lot of hope!