White Button Mushroom Extract in Treating Patients With Recurrent Prostate Cancer After Local Therapy

Inclusion Criteria: * Patients must have a histologically or cytologically confirmed history of adenocarcinoma of the prostate Patients must have a PSA failure defined as PSA of \>= 0.2 ng/ml that has increased above nadir following prostatectomy If radiation or other local therapy was used as a primary therapy and no prostatectomy was performed patients must have PSA increase of 2.0 above post-therapy nadir; PSA value must be increasing based on two consecutive measurements each separated by at least 2 weeks with no clinical or radiographic evidence of metastatic disease; PSA values that meet the criteria for eligibility within 4 weeks of registration are acceptable to document eligibility for enrollment on this study; PSA level obtained after registration and prior to the first course will be used as the "baseline" PSA as per the schema but will not determine eligibility for participation * Patients must have had at least three PSA measurements over a minimum of three months available prior to enrollment to this study * Patients may have received any number of local therapies (radical prostatectomy, external beam radiation therapy, radioactive seed implantation, cryotherapy) * Bone scan and computed tomography (CT) scan of the chest, abdomen and pelvis negative for metastatic disease within 2 months prior to registration * Patients must have a performance status of 0, 1, or 2 * All patients will have malignancy confirmed by review of their biopsy specimens by the Division of Pathology, City of Hope National Medical Center; if no pathological specimen is available for review, the patient may still be included if the patient has clearly documented prostate cancer per pathology report and a specimen request is documented as having been made for tissue from the outside facility but a specimen was unable to be obtained * Serum creatinine =\< 2.5 mg/dL * Baseline liver function tests including bilirubin =\< 1.5 x the institutional upper limit of normal and serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) =\< 2.5 x the institutional upper limit of normal * White blood cells (WBC) \>= 2000 * Platelets \>= 50,000 Exclusion Criteria: * Patients with evidence of metastatic disease * PSA progression not verified by sequential rising PSA as discussed in the eligibility section * Patients who have received prior cytotoxic chemotherapy or androgen ablative therapy for recurrent disease * Patients currently receiving biological response modifiers, or corticosteroids * Patients are permitted to have received up to 24 months of neoadjuvant or adjuvant hormone ablation in conjunction with their primary definitive therapy; androgen deprivation must have been completed at least 6 months prior to registration and testosterone level must be \> 50; no complementary or alternative therapy (e.g. St. John's Wort, PC-SPES, or other herbal remedies taken for the purpose of treating prostate cancer) may be given during protocol treatment; patients are allowed to have received neoadjuvant and/or adjuvant chemotherapy that was completed at least 6 months prior to registration to the protocol * Uncontrolled intercurrent illness including, but not limited to, ongoing active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/ social situations that would limit compliance with study requirements * Patients with known allergy to mushrooms