Prostate Cancer
Conditions
Keywords
stage IIB prostate cancer, stage IIA prostate cancer
Brief summary
RATIONALE: Soy protein may help prevent prostate cancer recurrence in patients who have undergone surgery for prostate cancer. PURPOSE: This randomized phase II/III trial is studying how well soy protein works and compares it to a placebo in preventing recurrent cancer in patients who have undergone surgery for stage II prostate cancer.
Detailed description
OBJECTIVES: * Determine whether soy protein isolate reduces the PSA failure rate and time to PSA failure within 2 years following radical prostatectomy in patients who are at high risk for prostate cancer recurrence. * Determine the effects of soy protein isolate on intermediate biomarkers of steroid hormone axis (testosterone, estradiol, and SHBG) and thyroid activity (T3 and T4). * Determine the effects of soy protein isolate on intermediate biomarkers of apoptosis (soluble Fas and Fas-ligand), angiogenesis (VEGF and bFGF), antioxidant activity (8-isoprostanes), and IGF axis (IGF-1 and IGFBP-3). * Compare patients who are equol producers to those who are non-producers. OUTLINE: This is a multicenter study. Patients are stratified according to hospital/clinic site (NYU vs UIC or Jesse Brown VA Medical Center vs other sites), number of high-risk characteristics (1 vs \> 1), and race (African American vs non-African American \[i.e., non-Hispanic White, Hispanic, Asian, and other\]). Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive an oral soy protein isolate beverage once daily. * Arm II: Patients receive an oral casein placebo beverage once daily. Treatment in both arms continues for up to 2 years in the absence of disease progression or unacceptable toxicity. Blood samples are collected periodically for biomarker laboratory studies. Samples are analyzed to measure PSA levels by Tosoh PSA assay; cholesterol levels; isoflavone and equol concentrations by HPLC and ESA; and indicators of steroid hormone axis (testosterone, estradiol, and SHBG), indicators of thyroid activity (T3 and T4), indicators of apoptosis (soluble Fas and Fas-ligand), indicators of angiogenesis (VEGF and bFGF), indicators of oxidative stress (8-isoprostanes), and indicators of IGF axis (IGF-1 and IGFBP-3) by ELISA.
Interventions
DIETARY_SUPPLEMENTsoy protein isolate
Given orally
OTHERplacebo
Given orally
Sponsors
National Cancer Institute (NCI)
University of Illinois at Chicago
Study design
Allocation
RANDOMIZED
Primary purpose
TREATMENT
Masking
DOUBLE
Eligibility
Sex/Gender
MALE
Age
40 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
DISEASE CHARACTERISTICS: * Diagnosis of prostate cancer * Clinically localized (T1c or T2) disease * At high risk for recurrence, as defined by ≥ 1 of the following: * Preoperative PSA \> 20.0 ng/mL * Seminal vesicle invasion * Extracapsular extension (excluding the bladder neck) * Positive surgical margins (excluding apical margins) * Micrometastases in any removed pelvic lymph nodes * Final Gleason score of ≥ 8 * Must have undergone radical prostatectomy for prostate cancer within the past 4 months * Must have an undetectable PSA (\< 0.07 ng/mL) at baseline, as measured by Tosoh PSA assay * No clinical evidence of locally recurrent or metastatic disease PATIENT CHARACTERISTICS: * No significant intake of soy (i.e., more than once a week) at baseline including, but not limited to, any of the following: * Vegetarians who regularly consume soy products (e.g., tofu) * Individuals with customary Asian dietary habits, including regular intake of soy products * Individuals who use soy-based milk replacements * No anemia, iron deficiency problems, or subclinical iron deficiency at baseline * No diabetes * No thyroid disease * No requirement for a sodium-free diet * No substantive tendency to be constipated (i.e., ≥ grade 2 constipation experienced regularly) * No medical problem that would preclude the consumption of the soy containing beverage powder, including allergies against soy (or milk protein) * No concurrent major disease, including major mental disease or major substance abuse problems * No significant side effects from medication PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No concurrent radiotherapy or hormonal therapy * No other concurrent adjuvant therapy for prostate cancer
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Two-year PSA failure rate (as surrogate for recurrence) | — |
| Time to PSA failure | — |
Secondary
| Measure | Time frame |
|---|---|
| Steroid hormone axis as measured by serum testosterone, estradiol, and SHBG levels | — |
| Thyroid activity as measured by serum T3 and T4 levels | — |
| Apoptotic activity as measured by serum soluble Fas and Fas-ligand levels | — |
| Isoflavone uptake or compliance as measured by serum isoflavone concentration | — |
| Oxidative stress as measured by serum 8-isoprostane levels | — |
| IGF axis as measured by serum IGF-1 and IGFBP-3 levels | — |
| Equol production as measured by serum equol concentration | — |
| Angiogenesis as measured by serum VEGF and bFGF levels | — |
| Serum total cholesterol levels | — |
Countries
United States
Outcome results
None listed