Multicenter Simon two-stage single-arm phase II trial of tamoxifen 20mg PO daily until progression (PD)....Eligible pts had progressive metastatic NET and positive IHC expression of ER and/or PR ≧ 1%....Twelve pts (52%) had DCR at week 24. Median progression-free survival (PFS) was 8 months (interquartile range [IQR]: 3.7 to 12.1). Best response was stable disease in 11 pts and 8 had PD at week 12. Median PFS was 6.1 months (IQR: 3.5 – 8.4) vs 9.4 months (IQR: 3.9 – 14.6), according to ER/PR < or ≥ 30% (logrank p = 0.48)....Tamoxifen for ER/PR-positive NET pts is safe but offers modest antitumor effects.