When I had my breast cancer surgery the sentinel node was tested and came back with microscopic traces of cancer. It was then deemed necessary to have an Axillary Node Dissection where they take out a lot of lymph nodes in your arm pit to see the possibilities that the cancer has spread further in your body. Mine came back negative. But the damage was done.
When that many lymph nodes (20 in my case) are taken, the lymph system in your arm in permanently compromised and the risk of lymphedema is greatly increased. That would be my problem.
Now there is a new study (because the researchers needed to keep working), that says that if the sentinel node is positive, the better outcome for a patient is to have axillary node radiation instead of an axillary node dissection. There appears to be the same or lower risk of recurrence and the risk of lymphedema is substantially reduced.
This is clearly in the category of now they tell me. Damn. I have lymphedema which complicates my life - and has no cure.
I guess this is what research is all about - figuring out how to improve treatment so that they can prevent complications and reduce risks from previous treatment standards.