Would you give adjuvant Tamoxifen to a premenopausal with ER+/PR+/Her2- Stage IA [pT1a, pN0(I+1)] breast cancer s/p bilateral mastectomies?   

Yes.The presence of ER+ disease confers a small but real risk of distant recurrence, as evidenced by Pan et al., PMID 29117498. In the retrospective by Sasada et al., PMID 37688665, the absolute 10-year risk of recurrence for pT1a/b N0 was 2.6% (Dropped to 1.5% in the ET group, although this was not...