Progestin therapy in advanced breast cancer: megestrol acetate--an evaluation of 160 treated cases.

Progestin megestrol acetate treatment of 160 postmenopausal women with progressive metastatic breast cancer is evaluated. Objective remission was found in 48 patients (30%) and stabilization of disease occurred in 58 (36%) cases. In each of these response categories, the median time interval before subsequent progression took place was nine months. Patients with a postmenopausal age of more than five years showed a significantly higher remission rate than did younger patients. In addition, great differences in remission rates were apparent between groups of patients classified according to dominant sites and separate sites of lesions. The length of disease-free interval did not prove to be of great importance in predicting the remission. No great difference in remission rates were found between patients treated with megestrol acetate as the first hormonal treatment and those previously treated with hormones. Side effects were negligible; a moderate weight increase without demonstrated fluid retention was found during therapy in 10% of the cases. Toxicity was not encountered. Megestrol acetate therapy may be the first choice of treatment in late postmenopausal patients with soft tissue and lung metastases.