[Effects of high-dose medroxyprogesterone acetate in advanced breast cancer, with special reference to prior endocrine therapy and hormone receptors].

Forty-six patients with advanced breast cancer were treated orally with high-dose medroxyprogesterone acetate (MPA), and a 28% (2 CRs, 11 PRs) response rate was obtained. The patient groups that showed a favorable response to MPA were as follows: patients in a postmenopausal state, with soft tissue or bone metastases, with slow-growing tumors, without prior therapy or with good response to prior endocrine therapy, and with positive estrogen (ER)- and/or progesterone (PgR) receptors. Six of 10 patients who had responded to prior endocrine therapy responded to MPA, while only 2 of 23 who had not responded to prior endocrine therapy showed a good response to MPA.