Tamoxifen in disseminated breast cancer

86 postmenopausal women with disseminated breast cancer have been treated orally with 30 mg of Tamoxifen per day (ICI 46474, Nolvadex) for periods of 2 months or more. The overall responders were 28/86 (32.5%) with a median remission duration of 9 months. In 30 patients already shown to be resistant to cytotoxic chemotherapy. Tamoxifen was used as first hormonal agent; the remission rate in this group was 12/30 (40%), while it was 28.5% (16/56) in the others who had already received different hormonal treatment. In 6 early menopausal cases, the treatment had to be stopped for a dangerous 'worsening syndrome'. Other side effects were trivial. In 28/35 cases (80%), we have found the reappearance of a pattern of estrogenic activity in vaginal smears during treatment. Hence a 'simil-estrogen', more than an 'anti-estrogen' mechanism of action is postulated and a selecion of patients for treatment in the 'mid postmenopausal age' is recommended.