RATIONALE: Soy isoflavones may reduce the risk of some types of cancer. It is not yet known if isoflavones are effective in preventing the development of prostate cancer.

PURPOSE: Randomized clinical trial to study the effectiveness of isoflavones in preventing further development of cancer in patients who have stage I or stage II prostate cancer.

Condition

Treatment or Intervention

stage I prostate cancer stage II prostate cancer

Drug: multivitamins  Drug: soy protein isolate  Procedure: biologically based therapies  Procedure: cancer prevention intervention  Procedure: chemoprevention of cancer  Procedure: complementary and alternative therapy  Procedure: dietary intervention  Procedure: dietary modification  Procedure: herbal medicine / botanical therapy  Procedure: nutritional supplementation  Procedure: phytoestrogen therapy

Further Study Details: 

OBJECTIVES:

• Determine the effectiveness of isoflavones in producing a change in risk parameters, such as decrease in free testosterone, increase in sex-hormone-binding globulin and estradiol, and decrease in tumor progression and volume, as measured by decreasing prostate-specific antigen in patients with stage I or II prostate cancer.

OUTLINE: This is a randomized, double-blind study. Patients are stratified according to Gleason score (2-4 vs 5-6). Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive oral isoflavones twice daily and an oral multivitamin once daily for 12 weeks.
• Arm II: Patients receive oral placebo twice daily and an oral multivitamin once daily for 12 weeks.

PROJECTED ACCRUAL: A total of 148 patients will be accrued for this study within 3 years.

Ages Eligible for Study:  50 Years   -   80 Years,  Genders Eligible for Study:  Both

Criteria

DISEASE CHARACTERISTICS:

• Diagnosis of stage I or II prostate cancer
• Gleason score 2-6* NOTE: *Patients with a Gleason primary pattern 4 (4 + 1 or 4 + 2) are ineligible

PATIENT CHARACTERISTICS: Age:

• 50 to 80

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• No known history of hepatic disease

Renal:

• No known history of renal disease

Other:

• Close to ideal body weight (body mass index no greater than 32 kg/m^2)
• No known history of thyroid disease
• No allergy to study agent
• No other prior malignancy except nonmelanoma skin cancer
• No evidence of prostatitis or urinary tract infection
• Fertile patients must use effective contraception
• Omnivorous diet (no vegan or vegetarian diets)

PRIOR CONCURRENT THERAPY: Biologic therapy:

• No prior or concurrent biologic therapy for prostate cancer

Chemotherapy:

• No prior or concurrent chemotherapy for prostate cancer

Endocrine therapy:

• No prior or concurrent endocrine therapy for prostate cancer
• No concurrent thyroid hormone replacement medications

Radiotherapy:

• No prior or concurrent radiotherapy for prostate cancer

Surgery:

• No concurrent surgery

Other:

• At least 30 days since prior antibiotics
• At least 30 days since prior ingestion of a diet high in soy products
• No other prior or concurrent therapy for prostate cancer
• No concurrent diet high in soy products
• No concurrent nutritional supplements (e.g., retinoids, beta-carotene, and isoflavones)

Arizona
      CCOP - Western Regional, Arizona, Phoenix,  Arizona,  85006-2726,  United States; Recruiting
Florida
      H. Lee Moffitt Cancer Center and Research Institute at University of South Florida, Tampa,  Florida,  33612-9497,  United States; Recruiting
      Urology Associates of Pinnellas County, Clearwater,  Florida,  33756,  United States; Recruiting
Georgia
      Cancer Care and Research Pavilion at St. Joseph's/Candler, Savannah,  Georgia,  31405-6015,  United States; Recruiting
Missouri
      CCOP - Cancer Research for the Ozarks, Springfield,  Missouri,  65807,  United States; Recruiting
      Hulston Cancer Center at Cox Medical Center South, Springfield,  Missouri,  65807,  United States; Recruiting
      St. John's Regional Health Center, Springfield,  Missouri,  65804-2263,  United States; Recruiting
Texas
      CCOP - Scott and White Hospital, Temple,  Texas,  76508,  United States; Recruiting

Study chairs or principal investigators

N. B. Kumar, PhD, RD, FADA,  Study Chair,  H. Lee Moffitt Cancer Center and Research Institute   

Study ID Numbers:  CDR0000069097; MCC-0002; NCI-4031; NCI-P01-0195; NCT00027950
Record last reviewed:  February 2005
Last Updated:  March 10, 2005
Record first received:  December 7, 2001
ClinicalTrials.gov Identifier:  NCT00027950
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-04-08