The purpose of this research study is to determine if giving men with early stage (Grade
1-2) prostate cancer dietary supplement from soybeans called isoflavones, will change their
blood hormone levels. Isoflavones are substances found in a high concentration in soybeans
that are converted in the intestines to hormone-like compounds which are similar to
estrogen. They are also thought to have cancer fighting properties. Clinical trials suggest
that isoflavones can increase certain sex hormones, which results in the slower production
of prostate cancer cells. This study will determine if adding isoflavones (supplied as
Prevastein HC®) 80 mg/day in a pill form can change your risk factors that cause early stage
prostate cancer to progress to more advanced disease.
To prevent biasing the outcome of the study, this is a double-blind study design, where both
the trialists and the participants are blinded to the specific nature of the product
(isoflavones and placebo). Participants in both groups will be discouraged from increasing
their intake of dietary isoflavones in the form of tofu, soy beans, soy milk, etc. In
addition, the intervention does not include active counseling on dietary modification and
supplementation of any one group. Monthly appointments will be made for all participants
for data collection and toxicity assessment.
This is a controlled, randomized, double blinded clinical trial, having one experimental and
one control group (n - 75/arm). Participants in the experimental group will consume an
isoflavones supplement in the form of Prevastein HC®, which will deliver 80 mgs (40 mg/dose)
biologically active isoflavones and those in the control group will receive an
identical placebo. The isoflavones supplement and the placebo tablets will be manufactured
and packaged by Cognis Corporation.
1. Isoflavones will be supplied at no charge by Cognis Corporation, LaGrange, Illinois as
Prevastein HC®. Each Prevastein HC® tablet delivers 20 mg biologically active
isoflavones, which is available for absorption. Participants will consume 2 tablets
twice daily (with meals) in addition to their usual diet.
2. Placebo will be supplied at no charge by Cognis Corporation, LaGrange, Illinois as an
indistinguishable tablet. Participants will consume 2 tablets twice daily (with meals)
in addition to their usual diet.
3. A standardized multivitamin will be supplied at no charge.
- Males, between the ages of 50 and 80
- Diagnosed with grade 1-2 prostate cancer (Gleason Score 2 to 6) Note: patients with a
Gleason primary pattern 4 (4+1 or 4+2) are not eligible.
- No prior or current therapy for prostate cancer
- No other history of cancer except non-melanoma skin cancer
- No known history of hepatic and/or renal disease
- No evidence of prostatitis or urinary tract infection (men being treated with
antibiotics may be enrolled 30 days after completion of therapy given that they still
meet all other eligibility criteria)
- No antibiotic use within 30 days of registration
- Close to ideal body weight(Body Mass Index no greater than 32 Kg/m²)
- Omnivorous diet
- Able and willing to give written consent
- Less than 50 years or over 80 years of age
- Prostate cancer beyond grade 2 (Gleason Score greater than 6)
- Gleason primary pattern 4 (4+1 or 4+2)
- Prior or planned treatment for prostate cancer of any stage
- Prior history of other cancer except non-melanoma skin cancer
- Current use of nutritional supplements, including modular supplements of other agents
with antioxidant properties e.g. retinoids, beta-carotene, and isoflavones
- Allergy to study agent
- Known history of hepatic or renal disease
- Body Mass Index greater than 32 Kg/m²
- Vegetarian/vegan diet
- Diet high in soy products (men who routinely consume a diet high in soy products may
be enrolled 30 days after eliminating soy product from the diet)
- Prostatitis or urinary tract infection
- Treatment with antibiotics within 30 days of registration