Androgen-induced remissions after antiestrogen and hypophysectomy in stage IV breast cancer.

Fluoxymesterone (Halotestin), 10 mg p.o. BID, was given to 33 women with Stage IV breast cancer who had previously been treated wih the antiestrogen tamoxifen (Nolvadex) and of whom 17 had also undergone hypophysectomy. Objective remissions were obtained in 13 patients (39%) with an average duration of 11+ months. Response rate to fluoxymesterone was similar in patients who had previously responded to tamoxifen and in those who had failed. Duration of response was longer in the former group (12+ vs. 8 months), but this difference was not statistically significant. Of 17 patients who had been previously treated with tamoxifen and hypophysectomy, seven obtained further remission from fluoxymesterone for an average duration of ten months. Two patients with remissions from fluoxymesterone had previously failed to respond both to antiestrogen therapy and to the removal of the pituitary gland. Androgens appear to be an effective sequential endocrine treatment of Stage IV breast cancer after tamoxifen and hypophysectomy. The mechanism by which androgens induce tumor regression in some patients is probably not an antiestrogenic effect or an indirect effect mediated through the pituitary gland, but perhaps a direct action at the tumor level.