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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00499408
Recruitment Status : Completed
First Posted : July 11, 2007
Results First Posted : February 17, 2014
Last Update Posted : November 21, 2018
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Wake Forest University Health Sciences

Brief Summary:

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 or disease Intervention/treatment Phase
Prostate Cancer Dietary Supplement: Vitamin D Dietary Supplement: soy Phase 2

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.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 26 participants
Intervention Model: Single Group Assignment
Masking: None (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
Study Start Date : April 2007
Actual Primary Completion Date : December 2012
Actual Study Completion Date : December 2012

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Soy and Vitamin D
Patients will receive oral supplementation with both 2,000 IU per day of vitamin D (cholecalciferol) and soy (160 mg per day soy isoflavones). Serum PSA and plasma levels of vitamin D will be assessed monthly. Soy isoflavones levels will be assessed every three months.
Dietary Supplement: Vitamin D
Patients will receive oral supplementation of 2,000 IU per day of vitamin D (cholecalciferol)
Other Name: cholecalciferol

Dietary Supplement: soy
Patients will receive oral supplementation of soy (160 mg per day soy isoflavones).
Other Name: isoflavones

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

Secondary Outcome Measures :
  1. Changes in PSA Slope [ Time Frame: up to one year ]
  2. Changes in PSA Doubling Time [ Time Frame: up to one year ]
  3. Number of Adverse Events, Grades 1-5 [ Time Frame: up to one year ]
    Toxicity will be graded according to the revised NCI Common Terminology Criteria for Adverse Events v 3.0, (CTCAE). Number of events with grade 1-5 will be reported.

  4. Time to Progression [ Time Frame: up to three years ]
    Progression will be defined as a 50% rise in serum PSA compared to the baseline value confirmed on at least two measurements at least two weeks apart.

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Ages Eligible for Study:   18 Years to 120 Years   (Adult, Older Adult)
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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): 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

Responsible Party: Wake Forest University Health Sciences Identifier: NCT00499408     History of Changes
Other Study ID Numbers: IRB00000371
P30CA012197 ( U.S. NIH Grant/Contract )
First Posted: July 11, 2007    Key Record Dates
Results First Posted: February 17, 2014
Last Update Posted: November 21, 2018
Last Verified: October 2018

Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No

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