Prostate Cancer Clinical Trial
Soy Protein in Preventing Recurrent Cancer in Patients Who Have Undergone Surgery for Stage II Prostate Cancer
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.
Full 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.
Eligibility 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
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There is 1 Location for this study
Chicago Illinois, 60612, United States
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