Further clinical studies with megestrol acetate in advanced breast cancer

A previous study showed activity of megestrol acetate in advanced breast cancer; as a result the study was expanded. Of 101 patients treated with this compound, 26 (26%) met our criteria of improvement. The drug was well tolerated and produced no toxicity and, as opposed to androgens and estrogens, no endocrine effects were observed. Prior hormonal or cytotoxic compounds, including alkylating agents, did not appear to reduce the subsequent responsiveness to this potent progestational compound. We now include it, often as the initial hormonal trial in postmenopausal patients, in our sequential treatment of disseminated breast cancer because of its favorable therapeutic ratio.