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 replacement and parameters of muscle strength would be improved by vitamin D replacement therapy. MATERIALS AND METHODS: After a 4-week placebo period, eligible patients received orally 2,000 units vitamin D daily for 12 weeks. Pain questionnaires and measurements of muscle strength were competed at study enrollment and every 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 cancer were enrolled in this phase II study, of whom 7 (44%) had decreased baseline vitamin D. With vitamin D treatment, 4 patients (25%) had improvement in pain scores and 6 (37%) had improvement in muscle strength measurements. Improvement in pain scores correlated with improvement in subjective symptoms but did not result in a significant decrease in regular scheduled analgesic requirements. CONCLUSIONS: Vitamin D deficiency develops in a significant percent of patients 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.