Soy Bread Diet in Improving Immune Function in Participants with Prostate Cancer

Inclusion Criteria

• Have biopsy-proven adenocarcinoma of the prostate (no small-cell, sarcomatoid, or other rare subtypes)
• Have completed local curative treatment, including prostatectomy, radiotherapy (XRT), or active surveillance. Men who present with metastatic disease not curable by local therapy are also eligible
• Be planning to begin a course of at least 5 months of androgen deprivation therapy (ADT). The ADT is defined as: (a) gonadotropin releasing hormone (GNRH) agonist (including leuprolide [Lupron/Eligard], goserelin [Zoladex], triptorelin [Trelstar], histrelin [Vantas], and abiratirone [Zytiga]) alone; (b) GNRH agonist with oral androgen receptor blockade (including bicalutamide [Casodex], flutamide [Eulexin], and enzalutamide [Xtandi]), and (c) GNRH agonist, oral androgen receptor blockade, and 5-alpha reductase inhibitors. We will not include men with only oral anti-androgen therapy, such as 5-alpha reductase inhibitors alone or oral antiandrogens alone, as they do not produce castrate levels of testosterone. Men may be included in the study if they have received only a brief course (up to 6 months) of ADT in the neoadjuvant setting at time of prostatectomy or in the adjuvant or salvage setting (provided the patient’s testosterone has recovered)
• Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1
• Have serum testosterone levels within normal limits
• Voluntarily agree to participate and a sign an informed consent document
• Be willing to discontinue all current vitamin/mineral supplements
• Agree to consume a standardized vitamin and mineral supplement (provided by the study) and avoid other nutrition, dietary, or alternative medications/supplements for the duration of the study

Exclusion Criteria

• Have an active malignancy other than prostate cancer that requires therapy
• Are undergoing any chemotherapy treatment for their prostate cancer
• Have any abnormal laboratory values that preclude starting hormone therapy for prostate cancer (PCa), as determined by a medical oncologist
• Are currently taking “complementary or alternative” products (i.e. PC-SPES, Saw Palmetto) that target the prostate or may impact the hormonal environment
• Not currently taking steroid medications
• No chronic infection (i.e., human immunodeficiency virus-positive [HIV+])
• Have any history of organ transplant requiring immunosuppressive medications
• Have renal insufficiency or follow a restricted protein diet for medical reasons
• Have certain medical conditions. Participants must have no allergy to soy, history of malabsorptive disorders, or other metabolic disorders requiring special diet recommendations (for example, Crohn’s disease or gluten enteropathy)