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

Study Overview
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Brief Summary
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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.

Detailed Description
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OBJECTIVES: 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.

Official Title
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Phase II Trial of Vitamin D and Soy Supplementation for Biochemically Recurrent Prostate Cancer Following Definitive Local Therapy

Conditions
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Prostate Cancer

Intervention / Treatment
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* Dietary Supplement: Vitamin D
* Dietary Supplement: soy


Participation Criteria
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Eligibility Criteria
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Inclusion: 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 Exclusion: 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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 120 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Soy and Vitamin D<br>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<br>* Patients will receive oral supplementation of 2,000 IU per day of vitamin D (cholecalciferol)<br>* Other names: cholecalciferol;Dietary Supplement: soy<br>* Patients will receive oral supplementation of soy (160 mg per day soy isoflavones).<br>* Other names: isoflavones;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Showing a 50% Reduction in Serum Prostate Specific Antigen(PSA) During Treatment |  | up to one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in PSA Slope |  | up to one year | 
| Changes in PSA Doubling Time |  | up to one year | 
| Number of Adverse Events, Grades 1-5 | 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. | up to one year | 
| Time to Progression | 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. | up to three years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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adenocarcinoma of the prostate, stage I prostate cancer, stage II prostate cancer, stage III prostate cancer