Is a tumor ever too small to send off a genomic assay like Oncotype or Mammoprint in HR positive, HER2 negative stage 1 breast cancer?  

There is a gray area in clinical decision making where the practice seems to be different for borderline size tumors such as a 7 mm T1b lesion with no other high risk features. Clinical practice seems to have wide variations based on institutional practices. 

Answer from: Medical Oncologist at Academic Institution