I cannot answer most of your questions; I will be checking back frequently to see if others do as I am interested in finding these things out myself. I am four years out from having breast cancer. I had neoadjuvant chemotherapy, then a bilateral mastectomy (my choice, I didn’t want to only have the affected breast removed), then radiation therapy. I have been on anastrozole for four years now ( I do have some side effects but they are not debilitating). I just had a checkup and my medical oncologist says we will do this test in six months to see if I should continue with the anastrozole for another five years. She said they test the actual tissue from my tumor which evidently was saved from my surgery.