A phase II study of high-dose medroxyprogesterone acetate in advanced breast cancer.

Twenty-three evaluable patients with advanced breast cancer were treated with MPA, 1,400 mg/m2 daily PO for the first 6 months, and 500 mg/m2 daily PO thereafter. The median total dose was 191,400 mg in 88 days, with the maximum dose given to date 522,600 mg in 282 days. Most patients tolerated high-dose MPA well. Side-effects were minimal and reversible. The commonest side-effects were tremor or edema. The CR plus PR rate was five of 23 (22%). All responding patients were over 50 years of age and had a good performance status. Hormone receptor status was known in four patients only, so that no correlation between receptor status and response could be drawn. MPA appears to be a useful hormone for use in the management of breast cancer. Optimal dosage remains to be determined.