High dose versus low dose medroxyprogesterone acetate: a randomized trial in advanced breast cancer.

One hundred and twenty-four patients with advanced breast cancer were randomly allocated to treatment with either low dose (300 mg/day) or high dose (1000 mg/day) oral medroxyprogesterone acetate. The objective response rate was 24% for both treatment groups. For premenopausal patients, responses were achieved in two out of four on low dose and three out of six on high dose therapy (overall 5 out of 10 responders). No significant differences in response were seen in relation to previous endocrine therapy or site of disease. Both treatments were associated with a high incidence of bone pain relief (43 and 52%) but a low objective response rate (13%) in bone. Median response duration (10 vs. 11 months) and survival (13 vs. 11 months) were not significantly different for the two treatments. Both treatments were in general well tolerated, but toxicity was greater with the high dose treatment. Low dose oral medroxyprogesterone acetate is as effective as high dose therapy in the treatment of advanced breast cancer, and is cheaper and less toxic.