Treatment of vitamin D deficiency in patients with metastatic prostate cancer may improve bone pain and muscle strength

Purpose: We performed a phase II study to determine whether pain associated with prostate cancer bone metastasis would respond to vitamin D replacemen t and parameters of muscle strength would be improved by vitamin D replacem ent therapy. Materials and Methods: After a 4-week placebo period, eligible patients rec eived orally 2,000 units vitamin D daily for 12 weeks. Pain questionnaires and measurements of muscle strength were competed at study enrollment and e very 4 weeks thereafter. Serum calcium and vitamin D were measured at each clinic visit. Results: A total of 16 patients with advanced hormone refractory prostate c ancer were enrolled in this phase II study, of whom 7 (44%) had decreased b aseline vitamin D. With vitamin D treatment, 4 patients (25%) had improveme nt in pain scores and 6 (37%) had improvement in muscle strength measuremen ts. Improvement in pain scores correlated with improvement in subjective sy mptoms but did not result in a significant decrease in regular scheduled an algesic requirements. Conclusions: Vitamin D deficiency develops in a significant percent of pati ents with advanced hormone refractory prostate cancer. Supplementation with vitamin D may be a useful adjunct for improving pain, muscle strength and quality of life in this patient population.