Men who have Prostate Specific Antigen (PSA) recurrence with low PSA levels and long doubling times do not require immediate treatment with androgen deprivation therapy and may be safely observed. In these situations where current treatment options may cause more unnecessary side effects than anticipated benefit, it is reasonable to use a low-risk natural product such as Acai Juice Product with antioxidant properties to evaluate whether there are any anti-cancer effects.

In this study, patients who meet eligibility criteria will take Acai Juice 2 ounces by mouth twice daily on a continuous basis.

Inclusion Criteria:

• Histologically confirmed prostate adenocarcinoma.
• Evidence of rising PSA, on 2 separate occasions, at least one week apart.
• Baseline PSA must be ≥ 0.2 ng/mL at the time of screening. Radiographic evidence of disease is not required.
• Patients must have sufficient PSA time points prior to enrollment (a minimum of 3 PSA levels within a six month period) to calculate a baseline PSA doubling time.
• Patients may not be on active Luteinizing Hormone Releasing Hormone (LHRH) agonist therapy and must have testosterone level > 50 ng/dL.
• Patients must not be on active anti-androgen therapy or 5-alpha reductase inhibitors. However, patients who have been on a stable dose of 5-alpha reductase inhibitor for benign prostatic hypertrophy for at least 6 months may continue taking this agent.
• Patients who are on active surveillance for localized disease may participate in this study.
• Patients who are candidates for local salvage therapy must have had this option pursued or discussed; and the patient must have either declined salvage therapy or was deemed not to be a candidate for salvage therapy.
• Patients who have PSA recurrence after local salvage therapy may participate in this study.
• Patients with hormone sensitive disease who received prior androgen deprivation therapy as part of primary/salvage local treatment or patients receiving intermittent androgen deprivation therapy will be allowed to participate.
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2.
• Adequate hematologic function (absolute neutrophil count (ANC) ≥ 1,500 cells/µL; hemoglobin ≥ 9 g/dL, platelets ≥ 75,000/µL).
• Adequate renal function (serum creatinine ≤ 2 X the ULN).
• Adequate hepatic function (total bilirubin ≤ 2 x upper limit of normal (ULN), alanine aminotransferase (ALT) ≤ 3 x ULN, aspartate aminotransferase (AST) ≤ 3 x ULN).
• Agree not to take any other forms of natural or herbal supplements during study duration.
• Chemotherapy for prostate cancer is allowed as long as it was not given for hormone-refractory disease.

Exclusion Criteria:

• Inability to swallow liquids, or any medical condition that interferes with normal gastrointestinal absorption.
• Major surgery, radiation, or treatment with any other investigational drug within 2 weeks of study treatment.
• Documented hypersensitivity reaction to acai or any product contained in Acai Juice (see complete list in Appendix 1).
• Uncontrolled intercurrent disease (e.g. diabetes, hypertension, thyroid disease, coronary artery disease).
• Known chronic infection with human immunodeficiency virus (HIV) or viral hepatitis.
• Symptomatic prostate cancer as determined by cancer-related pain requiring narcotic pain medication.
• History of another cancer is exclusionary unless it is believed to be likely cured or is unlikely to be fatal in the next 3 years (e.g. squamous cell carcinoma, superficial bladder cancer, chronic lymphocytic leukemia, etc).
• Very fast PSA doubling time of less than 4 weeks, if the absolute PSA is > 2 ng/mL.

From study start through study completion, an average of 1 year.