A randomized controlled comparative study of oral medroxyprogesterone acetate 1,200 and 600 mg in patients with advanced or recurrent breast cancer.

A randomized controlled comparative study of oral medroxyprogesterone acetate (MPA) 1,200 mg (arm I) and 600 mg (arm II) was conducted in 80 patients with advanced or recurrent breast cancer. There were no significant differences between arm I and arm II in terms of response rate, duration of response and survival, or in terms of incidence and severity of adverse reactions. The lowest serum MPA concentration in responders tended to be higher than that in nonresponders. In the cohort of this study, the lowest concentration in partial response was 17.4 ng/ml, suggesting that this level may be the required minimum serum concentration.