Effect of high-dose medroxyprogesterone acetate on plasma hormone levels and pain relief in patients with advanced prostatic cancer.

High-dose medroxyprogesterone acetate (MPA) was given orally to 7 patients with advanced prostatic cancer and severe pain due to bone metastases; 5 patients had stable and 2 had progressive disease. Pain relief was obtained in 6 patients. Two patients who reported complete relief of pain showed suppressed levels of gonadotrophins after MPA treatment. In the other patients, suppression of plasma gonadotrophin levels was observed before treatment. The plasma levels of prolactin, growth hormone and thyroid stimulating hormone were not affected by MPA. Only 1 patient showed suppression of plasma adrenocortical trophic hormone. The plasma levels of cortisol and dihydroepiandrosterone sulphate were suppressed in 6 patients, but there was no correlation between the suppression and the occurrence of pain relief. These findings suggest that the mechanism of pain relief by high-dose MPA may be very complicated.