Immunological Effects of Vitamin D Replacement Among Black/African American Prostate Cancer Patients

PRIMARY OBJECTIVE: I. Determine the changes in circulating immunological cell function among patients with vitamin D insufficiency and the effects of vitamin D replacement on those changes. SECONDARY OBJECTIVES: I. Determine the prevalence of vitamin D insufficiency among black / African American (AA) prostate cancer patients. II. Determine if there are differences in the peripheral blood immunological cell function in black/AA patients with metastatic or locally recurrent prostate cancer compared to those with localized prostate cancer. III. Determine if vitamin D replacement is associated with improvement in prostate-specific antigen (PSA) progression free survival (PSA-PFS) of black/AA patients with prostate cancer with detectable changes in immune response compared to those with no detectable changes in immune response and compared to stage matched historical controls. CORRELATIVE OBJECTIVE: I. Determine if there are differences in the peripheral blood immunological cell function in Black/AA patients compared to West African/Black patients from Nigeria. OUTLINE: Patients with low vitamin D3 levels receive cholecalciferol orally (PO) daily for 8 weeks in the absence of unacceptable toxicity. Patients undergo blood sample collection throughout the study. After completion of study treatment, patients are followed up at 56 days and then annually for 3 years.