In premenopausal woman tamoxifen is given after breast surgery

Sir in premenopausal woman tamoxifen is given after breast surgery and the drug should be continued for 10 years according to new guideline.
Sir if she got menopause(or age >50 yr achieved) then what should be regime… either continue tamoxifen or shift to anastrozole?

Start with Tam and switch to AI’s

thank you sir