Prostate specific antigen for assessing response to ketoconazole and prednisone in patients with hormone refractory metastatic prostate cancer.

Serial prostate specific antigen levels were assessed in 15 patients with hormone refractory metastatic prostate cancer treated with ketoconazole and prednisone. Of the men 12 (80%) with continually increasing prostate specific antigen levels before treatment had a decrease in prostate specific antigen with a median duration of response of 3 months. Three patients (20%) had a prolonged response (greater than or equal to 8 months) as seen by a persistently decreasing prostate specific antigen and improvement in bone pain. There appears to be a small subgroup of patients with progressive prostate cancer despite androgen ablation who will benefit from ketoconazole and glucocorticoid treatment. The use of serial prostate specific antigen levels appears to help define this subgroup and avoid the need for multiple radiological procedures to assess response.