Results of strontium-89 therapy in patients with prostate cancer resistant to chemotherapy

Purpose: Strontium-89 (Sr-89) chloride is an effective palliative treatment of the bone metastases of prostate cancer. Chemotherapy has also been shown to have a palliative benefit in this disease. We aimed to determine the benefits and complications of Sr-89 therapy in patients with prostate cancer who bad become refractory to chemotherapy. We conducted a retrospective review of 14 treatments administered to 13 patients with chemotherapy-resistant and hormone-resistant prostate cancer. Results: Of the 14 administered treatments, 8 (57%) resulted in improved pain control, with 2 patients able to stop analgesia. The median duration of response was 56 days. No prostate-specific antigen response was seen in the 8 patients tested. There was significant and prolonged bone marrow toxicity, with 6 patients requiring red blood cell transfusion. Prolonged thrombocytopenia was seen, with platelet counts remaining below baseline levels after treatment in all but one patient. Leukopenia was generally mild and not associated with infection. Conclusions: Sr-89 is an effective treatment of patients with chemotherapy-refractory prostate cancer, but careful and prolonged monitoring of hematologic parameters after therapy is required.