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Vitamin E, Selenium, and Soy Protein in Preventing Cancer in Patients With High-Grade Prostate Neoplasia

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: NCT00064194
Recruitment Status : Completed
First Posted : July 9, 2003
Last Update Posted : April 3, 2020
Information provided by (Responsible Party):
Canadian Cancer Trials Group ( NCIC Clinical Trials Group )

Brief Summary:

RATIONALE: Chemoprevention therapy is the use of certain substances to try to prevent the development or recurrence of cancer. Vitamin E, selenium, and soy protein may be effective in preventing the development of prostate cancer.

PURPOSE: Randomized phase III trial to study the effectiveness of combining vitamin E, selenium, and soy protein in preventing prostate cancer in patients who have high-grade prostate neoplasia.

Condition or disease Intervention/treatment Phase
Precancerous/Nonmalignant Condition Prostate Cancer Dietary Supplement: selenium Dietary Supplement: soy protein isolate Dietary Supplement: vitamin E Phase 3

Detailed Description:


  • Determine whether nutritional supplementation with soy protein isolate, vitamin E, and selenium can delay the time to development of invasive prostate cancer (disease-free survival) in patients with high-grade prostatic intraepithelial neoplasia.
  • Determine the effect of this supplementation on intermediate endpoints that may reflect a lessened risk of invasive prostate cancer (e.g., serum PSA levels, hormone levels, lycopene, malondialdehyde, vitamin E, and reduced thiol groups) in these patients.
  • Determine the safety of this supplementation in these patients.

OUTLINE: This is a randomized, double-blind, multicenter study. Patients are stratified according to participating center. Patients are randomized to 1 of 2 treatment arms.

  • Arm I: Patients receive oral vitamin E, oral selenium, and oral soy protein isolate twice daily.
  • Arm II: Patients receive oral placebo twice daily. In both arms, treatment continues for 3 years in the absence of invasive prostate cancer (demonstrated on biopsy) or unacceptable toxicity.

Patients are followed every 3 months for 1 year and then every 6 months for 2 years.

PROJECTED ACCRUAL: A total of 306 patients (153 per treatment arm) will be accrued for this study within 6 years.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 310 participants
Allocation: Randomized
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Prevention
Official Title: A Double-Blind, Placebo-Controlled, Randomized Study Of Combination Vitamin E, Selenium And Soy Protein Product In Subjects With High Grade Prostatic Intraepithelial Neoplasia
Actual Study Start Date : November 28, 2001
Actual Primary Completion Date : April 30, 2008
Actual Study Completion Date : April 30, 2008

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   up to 120 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No


  • Histologically confirmed high-grade prostatic intraepithelial neoplasia (HGPIN)

    • No evidence of invasive prostate cancer by at least 2 biopsies within the past 18 months
    • At least 1 biopsy must show evidence of HGPIN within the past 6 months
  • No prior invasive prostate cancer



  • Not specified

Performance status

  • Not specified

Life expectancy

  • More than 5 years


  • Platelet count at least 75,000/mm^3
  • No coagulopathies


  • Bilirubin no greater than 2 times upper limit of normal (ULN)
  • PT (INR) no greater than 1.5 times ULN
  • PTT no greater than 1.5 times ULN
  • No hepatic insufficiencies


  • Creatinine no greater than 2 times ULN
  • No renal insufficiencies


  • No prior nonmelanoma skin cancer (e.g., squamous cell or basal cell carcinoma)
  • No other malignancy within the past 5 years except superficial bladder cancer
  • No known bowel malabsorption
  • No dietary behavior (e.g., morbid obesity or eating disorders) that would limit adherence to study therapy
  • No major illness, including psychiatric illness, that would preclude study compliance and follow-up


Biologic therapy

  • Not specified


  • Not specified

Endocrine therapy

  • More than 3 months since prior androgen therapy
  • More than 3 months since prior hormonal therapy for benign prostatic hyperplasia (e.g., finasteride)
  • No concurrent finasteride
  • No concurrent androgen therapy


  • More than 2 years since prior radiotherapy to the pelvic region


  • Not specified


  • More than 2 weeks since prior supplemental vitamin E or selenium
  • No other concurrent vitamin E (greater than 100 IU/day), selenium, or soy protein isolate (more than 2 servings/week)
  • No other concurrent treatment for high-grade prostatic intraepithelial neoplasia

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): NCT00064194

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Canada, Nova Scotia
Nova Scotia Cancer Centre
Halifax, Nova Scotia, Canada, B3H 1V7
Canada, Ontario
Toronto Sunnybrook Regional Cancer Centre
Toronto, Ontario, Canada, M4N 3M5
Princess Margaret Hospital
Toronto, Ontario, Canada, M5G 2M9
Sponsors and Collaborators
NCIC Clinical Trials Group
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Study Chair: Neil Fleshner Princess Margaret Hospital, Canada
Publications of Results:
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Responsible Party: NCIC Clinical Trials Group Identifier: NCT00064194    
Other Study ID Numbers: PRP1
CAN-NCIC-PRP1 ( Other Identifier: PDQ )
CDR0000310096 ( Other Identifier: PDQ )
First Posted: July 9, 2003    Key Record Dates
Last Update Posted: April 3, 2020
Last Verified: April 2020
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Canadian Cancer Trials Group ( NCIC Clinical Trials Group ):
prostate cancer
high grade prostatic intraepithelial neoplasia
Additional relevant MeSH terms:
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Prostatic Neoplasms
Precancerous Conditions
Prostatic Intraepithelial Neoplasia
Genital Neoplasms, Male
Urogenital Neoplasms
Neoplasms by Site
Genital Diseases, Male
Prostatic Diseases
Carcinoma in Situ
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type
Vitamin E
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents
Trace Elements