This is not only acceptable, it is the most up-to-date approach.
A recent study confirmed the long
superior efficacy and safety of anastrozole (Arimidex
) over tamoxifen as initial adjuvant therapy for postmenopausal women with hormone-sensitive early breast cancer.
It is apparently considered likely that this would hold true for the other AIs, such as Aromasin, but if you wish, you could ask your doctor about the possibility of trying Arimidex in place of Aromasin.