I need to know how long Anastrozole lasts in my system. I had a lumpectomy and 18 days of radiation ending 6/22/17, I still am totally fatigued and weak. I had a brain tumor 30 years ago in Aug 1987, had 32 days of radiation as the tumor - noncancer was wrapped around brainstem. I had a stroke may 2010 and have loss of balance and require a cane or a walker. Per my doctor, I have a 6% chance of cancer returning and I am 68 years old. I do not want to take the medication if I end up with a lot of side effects, but I am willing to try but I need to know how long it would stay in my system with the side effects. I need to improve the quality of my life!! Thank you, Mary Kay