Clinical Trial: Soy Isoflavones in Treating Patients Who Are Undergoing Radical Prostatectomy for Stage I or Stage II Adenocarcinoma of the Prostate

This study is currently recruiting patients.

Sponsors and Collaborators: Barbara Ann Karmanos Cancer Institute
National Cancer Institute (NCI)
Information provided by: National Cancer Institute (NCI)


RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent or delay the development of early cancer. Soy isoflavones may be effective in delaying the development of early prostate cancer.

PURPOSE: This randomized phase II trial is studying different regimens of soy isoflavones to compare how well they work in treating patients who are undergoing radical prostatectomy for stage I or stage II prostate cancer (adenocarcinoma).

Condition Treatment or Intervention Phase
stage I prostate cancer
stage II prostate cancer
adenocarcinoma of the prostate
 Drug: soy protein isolate
 Procedure: cancer prevention intervention
 Procedure: chemoprevention of cancer
 Procedure: complementary and alternative therapy
 Procedure: conventional surgery
 Procedure: neoadjuvant therapy
 Procedure: surgery
Phase II

MedlinePlus related topics:  Prostate Cancer

Study Type: Interventional
Study Design: Treatment

Official Title: Phase II Randomized Study of Soy Isoflavones Before Radical Prostatectomy in Patients With Stage I or II Adenocarcinoma of the Prostate

Further Study Details: 


OUTLINE: This is a randomized, double-blind, placebo-controlled, parallel-group study. Patients are stratified according to tumor stage (T1c vs T2). Patients are randomized to 1 of 4 treatment arms.

  • Arm I (control group): Patients receive oral placebo once daily.
  • Arm II: Patients receive oral soy isoflavones and oral placebo once daily.
  • Arm III: Patients receive a higher dose of oral soy isoflavones and oral placebo once daily.
  • Arm IV: Patients receive a higher dose (higher than arm III) of oral soy isoflavones once daily. In all arms, treatment continues for 2-6 weeks (depending on the time from study entry to planned surgery) in the absence of unacceptable toxicity. All patients then undergo radical prostatectomy.

Patients are followed at 1 week.

PROJECTED ACCRUAL: A total of 100 patients (25 per treatment arm) will be accrued for this study within 12.5 months.


Ages Eligible for Study:  18 Years and above,  Genders Eligible for Study:  Both




  • 18 and over

Performance status

  • Not specified

Life expectancy

  • Not specified


  • Not specified


  • ALT and AST less than 2 times upper limit of normal (ULN)
  • Alkaline phosphatase less than 2 times ULN


  • Not specified


  • Fertile patients must use effective barrier contraception
  • Medically cleared for surgery
  • No concurrent thyroid disease



Endocrine therapy


  • Not specified


  • See Disease Characteristics


  • At least 3 months since prior high-dose nutritional supplements
  • No concurrent regular use (more than once weekly) of soy products greater than 50 g of soy protein or 50 mg of soy isoflavone
  • No concurrent high-dose nutritional supplements
  • Standard-dose single multivitamin tablet (e.g., Centrum™) allowed
  • No concurrent herbs
  • No concurrent soy foods
  • No other concurrent isoflavone supplements
  • No other concurrent antineoplastic agents

Location and Contact Information

      Barbara Ann Karmanos Cancer Institute, Detroit,  Michigan,  48201,  United States; Recruiting
Omer Kucuk, MD  313-745-2748 

Study chairs or principal investigators

Omer Kucuk, MD,  Principal Investigator,  Barbara Ann Karmanos Cancer Institute   

More Information

Clinical trial summary from the National Cancer Institute's PDQ® database

Study ID Numbers:  CDR0000353197; WSU-C-2418; NCT00078923
Record last reviewed:  March 2005
Last Updated:  April 5, 2005
Record first received:  March 8, 2004 Identifier:  NCT00078923
Health Authority: United States: Federal Government processed this record on 2005-04-08

Cache Date: April 9, 2005