It matters as far as I'm concerned. My estrogen-fed grade 3 cancer apparently did not spread - as shown by a PET scan. But it was aggressive. There is no guarantee that it did not escape the lymph glands. Were I to disregard medical advice and stop taking 1mg anastrozole each day, I'd start worrying that every little twinge and pain might be caused by a tumour setting up shop somewhere. That would not be good for my mental health. Anyone can of course disregard the advice of their oncologist - the decision is always up to the patient- but he or she won't be the one living with the consequences. And you can always ask for a second or third opinion.