HIGH-DOSE MEDROXYPROGESTERONE ACETATE IN BREAST-CANCER RESISTANT TO ENDOCRINE AND CYTOTOXIC THERAPY

The therapeutic effects of high-dose (1000 or 1500 mg/day) medroxyprogesterone acetate (MPA) were evaluated in a consecutive series of 81 women with advanced breast cancer. All patients were resistant to either endocrine treatment and/or chemotherapy. Complete plus partial remission was obtained in 23 of 81 (28%) patients, with a median duration of 6 months and a median survival of 13.5 months. The highest response rate was observed with lung metastases (41%), followed by soft tissue (31%) and osteolytic bone involvement (13%). Complete plus partial response was not significantly influenced by the dose regimen utilized (32% with 1000 mg/day vs. 21% with 1500 mg/day). Responders survived longer than nonresponders. The responsiveness to MPA was correlated with the prior disease-free interval (≥2 years: 47%, < 2 years: 19%) and with menopausal status (17% in premenopausal vs. 32% in postmenopausal patients), but was independent of prior response to other hormonal manipulations and chemotherapy. An increase in body weight was observed in 56% of cases and gluteal abscess in 16%. The incidence of this latter side effect was correlated with the dose (1000 mg: 13%; 1500 mg: 21%). This study shows that high-dose MPA can produce objective remission with improved survival in about one-third of postmenopausal women who are resistant to cytotoxic drugs and other endocrine therapies. Our results are not superior to those obtained with conventional oral MPA. © 1979 Springer-Verlag.