Multicenter study of trilostane: a new hormonal agent in advanced postmenopausal breast cancer.

: Trilostane, an inhibitor of the production of adrenal estrogens, was administered, together with dexamethasone, to 97 eligible postmenopausal women with advanced breast cancer. Seventy-four patients who had either received trilostane for a minimum of 10 weeks or whose disease had progressed while on trilostane before this period were assessed for tumour response. Eighteen patients (25%) had objective responses (two complete, 16 partial); a further 21 patients had stable disease. The response rate among all 97 patients, including those not treated for a minimum 10-week period, was 19%. Thirty-two of 97 patients reported adverse reactions which were attributed to trilostane and/or dexamethasone. Therapy was stopped for 15 patients, and the dose of trilostane was reduced for ten. Diarrhea was the commonest side effect, being reported in 16 patients, of whom nine stopped treatment. Trilostane, given with a corticosteroid, is an effective alternative hormonal agent acting by adrenal blockade for postmenopausal women with advanced breast cancer.