A phase-III prevention trial of low-dose tamoxifen in postmenopausal hormone replacement therapy users: the HOT study

2 Results: After 6.2 ± 1.9 years mean follow-up, there were 24 breast cancers on placebo and 19 on tamoxifen (risk ratio, RR, 0.80; 95% CI 0.44-1.46). Tamoxifen showed favorable trends in luminal-A tumors (RR, 0.32; 95% CI 0.12-0.86), in HRT users <5 years (RR, 0.35; 95% CI 0.15-0.82) and in women completing at least 12 months of treatment (RR, 0.49; 95% CI 0.23-1.02). Serious adverse events did not differ between placebo and tamoxifen, including, respectively, coronary heart syndrome (6 versus 4), cerebrovascular events (2 versus 5), VTE (2 versus 5) and uterine cancers (3 versus 1). Vasomotor symptoms were 50% more frequent on tamoxifen. Conclusions: The addition of low-dose tamoxifen to HRT did not significantly reduce breast cancer risk and increased climacteric symptoms in recently postmenopausal women. However, we noted beneficial trends in some subgroups