Prostate specific antigen levels and clinical response to low dose dexamethasone for hormone-refractory metastatic prostate carcinoma

BACKGROUND: It has been suggested that suppression of adrenal androgens may provide benefit to patients with metastatic prostate cancer refractory to initial hormonal therapy (e.g., orchiectomy). METHODS: The records of 38 patients with metastatic prostate cancer that had progressed after orchiectomy who were placed subsequently on low dose dexamethasone (DXM) with no other concurrent therapy (36 patients received 0.75 mg twice daily and two received 0.75 mg three times daily) were reviewed. Symptomatic status, prostate specific antigen (PSA) measurements, and available radiographic assessments were recorded. Bone scans were reviewed by an independent, blinded evaluator. RESULTS: Symptomatic improvement was experienced by 24 patients (63%), 20 (83%) of whom also had decreases in PSA. Prostate specific antigen values decreased in 30 patients (79%) with decreases 50% or greater and 80% or greater in 23 (61%) and 13 (34%) patients, respectively. Of the 23 patients with PSA decreases 50% or greater, 8 (35%) had radiographic evidence of disease regression, 5 (22%) were stable, 7 (30%) had disease progression, and 3 (13%) did not have serial radiographic exams. Flutamide was discontinued shortly before DXM treatment for 2 of the 23 patients. CONCLUSIONS: Low dose DXM may produce important symptomatic improvement and decreased PSA levels in the majority of patients with hormone-refractory prostate cancer. In addition, a substantial percentage of those patients with decreases in PSA also will have radiographic evidence of disease regression. These results suggest the need for additional prospective controlled studies of DXM as a therapy for hormone-refractory prostate cancer.