Soy Protein in Preventing Recurrent Cancer in Patients Who Have Undergone Surgery for Stage II Prostate Cancer

Last updated: September 19, 2013
Sponsor: University of Illinois at Chicago
Overall Status: Completed

Phase

2/3

Condition

Urologic Cancer

Prostate Cancer

Prostate Cancer, Early, Recurrent

Treatment

N/A

Clinical Study ID

NCT00765479
CDR0000615902
UIC-2006-0706
  • Ages 40-75
  • Male

Study 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.

Eligibility Criteria

Inclusion

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

Study Design

Total Participants: 284
Study Start date:
December 01, 2006
Estimated Completion Date:
July 31, 2013

Study 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.

Connect with a study center

  • University of Illinois Cancer Center

    Chicago, Illinois 60612-7243
    United States

    Site Not Available

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