Women with hormone receptor-positive breast cancer who have gone through menopause at the time of diagnosis have three options for adjuvant hormonal therapy:

• They can begin treatment with either an AI or tamoxifen for five years.
• They can begin treatment with tamoxifen for two to three years and then switch to an AI for up to five years.
• Some women may switch to an AI after five years of treatment with tamoxifen; this is called extended therapy.

Because AIs only work in postmenopausal women, it is important that a woman is actually postmenopausal before considering an AI. At this time, it is not known which treatment option is better. Women who cannot tolerate one of these options should talk with their doctors about switching treatments.

Women who might be advised to consider using an AI only:

• Women who cannot take tamoxifen because of a high risk of side effects
• Women who tried tamoxifen and stopped therapy because of side effects
• Any woman who has gone through menopause and has hormone receptor-positive breast cancer who would prefer to take an AI instead of tamoxifen as the initial treatment

Women who might be advised NOT to consider using an AI:

• Women who experience intolerable side effects while taking an AI, or who are concerned about the side effects of AI therapy.
• Women who have not gone through menopause.