An evaluation of high-dose medroxyprogesterone acetate (MPA) therapy in women with advanced breast cancer.

The efficacy of high-dose intramuscular MPA therapy in controlling progressive measurable metastatic breast carcinoma was assessed in 32 women. In addition serial measurements of MPA blood levels were carried out in 20 of the patients and subjective effects of treatment were monitored in detail in 18 of the women. Overall 6 patients (19%) gained an objective response and a further 7 (22%) experienced disease stasis from 4-17 months whilst on treatment. Significant differences in serum MPA levels were seen between responders and non-responders, objective tumour shrinkage only being seen in those patients who rapidly attained, and sustained, blood levels in excess of 100 ng ml-1. Subjective assessment showed no evidence of a euphoriant effect of MPA therapy in the non-responders group.