Effective and economical option for pain palliation in prostate cancer with skeletal metastases: 32P therapy revisited.

The role of phosphorus-32 (32P) was evaluated in patients experiencing pain due to skeletal metastases from prostate cancer and refractory to other modes of treatment. Twenty patients received 185 MBq (5 mCi)32P intravenously; 12 patients received a single dose each, five patients were injected twice and three patients three times at 3-month intervals. A blood count and clinical assessment for bone pain, tender sites, mobility and analgesic intake were performed before and 4, 8 and 12 weeks after the administration of 32P. A bone scan was performed before and 12 weeks after therapy. The results showed a significant decrease in pain at 4 weeks and a palliative response persisted for up to 12 weeks. Analgesic medication intake decreased significantly (F = 13.2213, P < 0.0001) and mobility improved after therapy. Quantitative analysis of the bone scans showed a statistically significant reduction in osteoblastic activity in metastatic lesions after therapy (t = -3.80, P < 0.001). Transient myelosuppression after 4 weeks, which was statistically significant for WBC and platelet counts only (F = 3.0226, P = 0.0358; F = 6.2514, P = 0.0009 respectively), returned within normal limits by 8 weeks. We conclude that 32P is an effective and safe therapy for pain palliation.