I think the 53% of reduction, to which this article refers, is prevention in women who are at risk for developing breast due to genetic factors or family history, for example, not for women who already have breast cancer. I have read that the risk reduction benefit from taking an aromatase inhibitor (AI) for 5 - 10 years after being diagnosed with ER+ breast cancer and after having had surgery and possibly radiation is 40% to 60%.
I was told that my chance of recurrence was 12% without taking an AI.
If I took an AI for at least 5 years, my risk would be between 7.2% and 4.8%. I had MANY side effects from anastrozole, the worst being severe depression and an overall poor quality of life. I was encouraged to try exemestane, but I declined. The hope of potentially reducing my risk of recurrence by less than 5%, was not worth feeling so awful for 5 -10 years, so I decided to stop taking anastrozole after 2 1/2 months. That was 4 years ago. I will be 75 in May. So far, I am doing well. I walk every day and eat a good diet.
I am not suggesting that anyone stop taking these drugs. It's a difficult, personal decision. Just know that it is your decision to make based on your situation and how you feel. I wish you all well. Try to be at peace with whatever decision you make. Sending hugs.