Cholecalciferol and Genistein Before Surgery in Treating Patients With Early Stage Prostate Cancer

This randomized phase II trial studies cholecalciferol and genistein compared to placebo in treating patients with early stage prostate cancer. Cholecalciferol and genistein may slow the growth of cancer cells and may be an effective treatment for prostate cancer.

PRIMARY OBJECTIVES:

I. To determine differences in prostate tissue steady state concentrations of calcitriol in participants treated with a single dose cholecalciferol (200,000 IU) and G-2535 (which provides 600 mg of genistein) and those receiving placebo.

SECONDARY OBJECTIVES:

I. To determine the effect of each intervention arm and resulting prostate tissue levels of calcitriol on down-stream related biomarkers and related mechanistic pathways in blood and tissue.

OUTLINE: Patients are randomized to 1 of 2 treatment arms.

ARM I: Patients receive cholecalciferol orally (PO) on day 1 and genistein PO once daily (QD) on days 1-21 or 1-28. Patients then undergo prostatectomy.

ARM II: Patients receive placebo PO on day 1 and placebo PO QD on days 1-21 or 1-28. Patients then undergo prostatectomy.

Eligibility Criteria:
Inclusion Criteria:

* Participants must have microscopic confirmation of adenocarcinoma of the prostate within three months of randomization; clinical stage T1 and T2 a, b, or c are allowed
* Participants' prostate cancer must be confined to the prostate (in the clinical judgment of the treating physician)
* Participants must be candidates for prostatectomy
* Participants must have Eastern Cooperative Oncology Group (ECOG) performance status =\<1 (Karnofsky \>= 70%)
* White blood cell (WBC) within normal limits
* Platelets \>= 100 K/uL
* Hemoglobin \>= 10 g/dL
* Thyroid-stimulating hormone (TSH) =\< 4.20 uIU/mL
* Free T4 =\< 12.5 ng/dL
* Bilirubin within upper limit of normal
* Aspartate aminotransferase (AST) =\< 1.5 x upper limit of normal
* Creatinine =\< 2.0 mg/dL
* Serum calcium: within institutional normal limits
* Participants must agree to stop taking nonsteroidal anti-inflammatory drugs (NSAIDS) during the course of the study, however, low dose aspirin (\< 100 mg/day) will be allowed; no wash out period is required
* Participants must be willing to discontinue consuming soy products and ingesting vitamin supplements while participating in this study
* The effects of cholecalciferol and genistein on the developing human fetus at the recommended therapeutic doses are unknown; for this reason, participants must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) for the duration of study participation
* Participants must have the ability to understand and sign a consent form indicating the investigational nature of the treatment and its potential risks

Exclusion Criteria:

* Participants may not have received any prior therapy for prostate cancer including: chemotherapy, hormonal therapy, brachytherapy, or external radiation
* Participants may not be receiving concurrent systemic therapy for other cancers
* Participants may not be receiving any other investigational agents
* Participants may not be taking the following p450 inducers and inhibitors: carbamazepine, clarithromycin, fluconazole, fosphenytoin, itraconazole, ketoconazole, phenobarbital, phenytoin, rifabutin, rifampin
* Participants who took finasteride or dutasteride within 6 months of the pre-randomization biopsy, are currently taking finasteride or dutasteride, or are planning on taking these agents during study participation
* Participants with a history of allergic reactions attributed to genistein or placebo, or compounds of similar chemical or biologic composition
* Participants with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
* Participants requires thyroid replacement therapy; Note: participants with a history of thyroid disease \> 5 years ago, with current normal thyroid function, will be considered eligible
* Participant has current, known nephrolithiasis or a history of nephrolithiasis within the past 5 years
* Participant has any history of sarcoidosis