Weighing Choices

So here's my summary. If I magically knew my tumor grade --
1. Non-tumor (learn from test): no surgery
2. Grade I: no surgery
3. Grade II: no surgery
4. Grade II with III (or III): surgery

If it is a tumor, here's what I have learned:
1. Not relevant
2. Grade I -- less likely given my age
3. Grade I or II -- 70%-85% likelihood
4. Grade II mixed with III (or III) -- 15% likelihood, could be up to 30%

If I choose surgery it would be because I want to know if I have grade III cells so I can have it treated. So, I want to find out how reliable MRI scanning is in telling me whether my tumor is transforming. If it is reliable, then I could wait. But, nothing will tell me if I already have grade III cells, nothing but surgery.