antineoplastic hormone, a chemically synthesized or a synthetic analog of the naturally occurring compound used to control certain disseminated cancers. Hormonal therapy is designed to counteract the effect of an endogenous hormone required for tumor growth. The estrogens diethylstilbestrol (DES) and ethinyl estradiol may be used in the palliative treatment of a prostatic carcinoma that is nonresectable or unresponsive to radiotherapy. An androgen, such as testosterone propionate, testolactone, or fluoxymesterone, may be administered after surgery to control disseminated breast cancer in women whose tumor is estrogen dependent. The antiestrogen tamoxifen produces responses in many patients with advanced estrogen-dependent breast cancer. Paradoxically, large doses of estrogen, frequently used to control disseminated breast cancer in postmenopausal women, apparently check the growth of tumors by inhibiting the secretion of estrogen by the adrenal gland. Some progestins produce a favorable response in women with disseminated endometrial carcinoma and, occasionally, in patients with prostate or renal cancers. These progestins include megestrol acetate, medroxyprogesterone acetate, and 17-alpha-hydroxyprogesterone caproate.
