Tamoxifen versus high-dose oral medroxyprogesterone acetate as initial endocrine therapy for patients with metastatic breast cancer: a Piedmont Oncology Association study.

PURPOSETo determine in a prospective randomized trial whether high-dose orally administered medroxy-progesterone acetate (MPA) was superior to tamoxifen in patients with recurrent or metastatic breast cancer who had received no prior endocrine therapy in either the adjuvant or advanced setting.PATIENTS AND METHODSPatients initially received either tamoxifen 20 mg/d orally or MPA 1 g/d orally. At the time of disease progression, patients were crossed over to the other regimen. Eligibility required patients to be age > or = 18 years, performance status 0 to 3, and estrogen receptor (ER)- or progesterone receptor (PR)-positive or unknown.RESULTSOne hundred eighty-two eligible patients were entered and 166 were assessable for response. Complete plus partial response rates for tamoxifen and MPA were 17% and 34%, respectively (P = .01). Patients with bone metastases had a significantly higher partial response rate with MPA compared with tamoxifen (33% v 13%). Median time to treatment failure was 5.5 months for ...