Vitamin D and Soy Supplements in Treating Patients With Recurrent Prostate Cancer
RATIONALE: Vitamin D and soy extract may be effective in lowering prostate-specific antigen (PSA) levels in patients with recurrent prostate cancer that has not responded to previous treatment.
PURPOSE: This phase II trial is studying how well giving vitamin D together with soy supplements works in treating patients with recurrent prostate cancer.
Dietary Supplement: cholecalciferol
Dietary Supplement: genistein
Dietary Supplement: soy isoflavones
Genetic: polymerase chain reaction
Genetic: protein expression analysis
Other: immunologic technique
Other: laboratory biomarker analysis
|Study Design:||Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Phase II Trial of Vitamin D and Soy Supplementation for Biochemically Recurrent Prostate Cancer Following Definitive Local Therapy|
- Number of Participants Showing a 50% Reduction in Serum Prostate Specific Antigen(PSA) During Treatment [ Time Frame: up to one year ] [ Designated as safety issue: No ]
- Changes in PSA Slope [ Time Frame: up to one year ] [ Designated as safety issue: No ]
- Changes in PSA Doubling Time [ Time Frame: up to one year ] [ Designated as safety issue: No ]
|Study Start Date:||April 2007|
|Primary Completion Date:||December 2012 (Final data collection date for primary outcome measure)|
- Test the response of biochemically recurrent prostate cancer to a combination of cholecalciferol (i.e., vitamin D) and soy isoflavones (i.e., soy extract) after failed definitive local therapy as determined by PSA response.
OUTLINE: Patients receive oral cholecalciferol twice daily and a soy supplement (i.e., soy bar or shake) once daily. Treatment continues for 3-12 months in the absence of disease progression or unacceptable toxicity.
Blood samples are obtained at baseline and periodically during study to measure serum PSA, serum calcium, plasma cholecalciferol, and plasma soy isoflavone levels. Blood samples are also analyzed for expression of cholecalciferol receptor, p21, and p27 in peripheral blood lymphocytes as surrogate markers of the actions of cholecalciferol and genistein. Protein expression is assessed by immunoblot analysis of cell lysates as well as quantitative polymerase chain reaction.
Patients complete a toxicity questionnaire once each month to assess for cholecalciferol and soy supplementation toxicities and symptoms of hypercalcemia.
After completion of study therapy, patients are followed every 3 months for 1 year.
|United States, North Carolina|
|Wake Forest University Comprehensive Cancer Center|
|Winston-Salem, North Carolina, United States, 27157-1096|
|Study Chair:||K.C. Balaji, MD||Comprehensive Cancer Center of Wake Forest University|