Treatment of advanced breast cancer with megestrol acetate after therapy with tamoxifen.

The efficacy of megestrol acetate in the treatment of advanced (Stage IV) carcinoma of the breast was studied in 48 evaluable patients who had been initially treated with tamoxifen. Forty-five patients had previously responded to the tamoxifen therapy. Fifteen patients (31%) had partial remissions, sixteen patients (33%) had stable disease, and seventeen patients (36%) had progressively disease. The median response duration was seven months for responding patients and six months for disease-stable patients. These results suggest that megestrol acetate is an effective agent for the palliation of advanced breast cancer relapsing following response to tamoxifen therapy.