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Vitamin D and Soy Supplements in Treating Patients With Recurrent Prostate Cancer

This study has been completed.
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Wake Forest University Health Sciences Identifier:
First received: July 10, 2007
Last updated: March 13, 2017
Last verified: March 2017

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.

Condition Intervention Phase
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
Phase 2

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: No masking
Primary Purpose: Treatment
Official Title: Phase II Trial of Vitamin D and Soy Supplementation for Biochemically Recurrent Prostate Cancer Following Definitive Local Therapy

Resource links provided by NLM:

Further study details as provided by Wake Forest University Health Sciences:

Primary Outcome Measures:
  • Number of Participants Showing a 50% Reduction in Serum Prostate Specific Antigen(PSA) During Treatment [ Time Frame: up to one year ]

Secondary Outcome Measures:
  • Changes in PSA Slope [ Time Frame: up to one year ]
  • Changes in PSA Doubling Time [ Time Frame: up to one year ]

Enrollment: 26
Study Start Date: April 2007
Study Completion Date: December 2012
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Detailed Description:


  • 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.


Ages Eligible for Study:   18 Years to 120 Years   (Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No


  • Age > 18 years
  • Histologically confirmed adenocarcinoma of the prostate
  • Biochemical relapse following definitive therapy by ASTRO criteria (PSA with 3 consecutive rising measurements separated by at least one month) and minimum PSA ≥ 1.0 ng/mL
  • PSA doubling time of ≥ 6 months, as demonstrated by 3 PSA measurements obtained ≥ 2 months apart
  • No hormonal therapy in 6 months prior to enrollment
  • ECOG performance status 0-2
  • Life expectancy > 3 months
  • At least 2 years since prior definitive radiotherapy
  • No concurrent cholecalciferol, calcium, or soy supplements
  • Absolute granulocyte count ≥ 1,000/mm³
  • Platelet count ≥ 100,000/mm³
  • Hemoglobin ≥ 9.0 g/dL
  • Creatinine ≤ 2.0 mg/dL
  • Total bilirubin ≤ 2.0 mg/dL
  • Calcium > 8.5 mg/dL and < 10.5 mg/dL
  • Testosterone ≥ 150 ng/dL


  • No clinically evident brain metastases
  • Concurrent cholecalciferol, calcium, or soy supplements
  • Concurrent chemotherapy with nonstudy drugs
  • Serious medical illness that would limit survival to < 3 months, or psychiatric condition that would preclude giving informed consent
  • Other malignancy except nonmelanoma skin cancer, adequately treated stage I or II cancer from which the patient is currently in complete remission, or any other cancer from which the patient has been disease-free for the past 5 years
  • Active, uncontrolled bacterial, viral, or fungal infection
  • Hemorrhagic disorder
  • Evidence of metastatic disease by bone scan or CT scan
  • History of hypercalcemia
  • More History of exposure to other phytotherapeutics, including PC-SPES and Saw Palmetto, within the last year.
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Please refer to this study by its identifier: NCT00499408

United States, North Carolina
Wake Forest University Comprehensive Cancer Center
Winston-Salem, North Carolina, United States, 27157-1096
Sponsors and Collaborators
Wake Forest University Health Sciences
National Cancer Institute (NCI)
Study Chair: K.C. Balaji, MD Wake Forest University Health Sciences
  More Information

Responsible Party: Wake Forest University Health Sciences Identifier: NCT00499408     History of Changes
Other Study ID Numbers: CDR0000554969
P30CA012197 ( US NIH Grant/Contract Award Number )
Study First Received: July 10, 2007
Results First Received: November 15, 2013
Last Updated: March 13, 2017

Keywords provided by Wake Forest University Health Sciences:
adenocarcinoma of the prostate
stage I prostate cancer
stage II prostate cancer
stage III prostate cancer

Additional relevant MeSH terms:
Prostatic Neoplasms
Genital Neoplasms, Male
Urogenital Neoplasms
Neoplasms by Site
Genital Diseases, Male
Prostatic Diseases
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents
Anticarcinogenic Agents
Protective Agents
Antineoplastic Agents
Protein Kinase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Estrogens, Non-Steroidal
Hormones, Hormone Substitutes, and Hormone Antagonists processed this record on April 28, 2017