RATIONALE: Pomegranate juice may contain substances that decrease or slow the rise of prostate-specific antigen (PSA) levels and may be effective in delaying or preventing recurrent prostate cancer.

PURPOSE: This phase II trial is studying how well pomegranate juice works in decreasing or slowing the rise of PSA levels in patients who have undergone radiation therapy or surgery for prostate cancer.

OBJECTIVES:

• Determine whether pomegranate juice can decrease or slow rising prostate-specific antigen (PSA) levels in patients who have undergone radical prostatectomy or radiotherapy for adenocarcinoma of the prostate.

OUTLINE: Patients receive oral pomegranate juice once daily. Treatment continues for 18 months in the absence of disease progression or unacceptable toxicity.

PROJECTED ACCRUAL: A total of 29-40 patients will be accrued for this study.

Inclusion Criteria:

• Histologically confirmed adenocarcinoma of the prostate
• Must have undergone prior surgery or radiotherapy for the primary tumor
• Documented rising prostate-specific antigen (PSA) level, defined by the following criteria:
• Absolute level of PSA at least 0.2 ng/mL but less than 5.0 ng/mL
• Rising PSA level must be confirmed at least 1 week later
• Adequate PSA time points to calculate a PSA doubling time
• Gleason score no greater than 7
• Age 18 and over
• Performance status ECOG 0-1
• Life expectancy at least 6 months
• No other malignancy within the past 5 years except nonmelanoma skin cancer
• No other serious concurrent systemic medical disorders that would preclude study compliance
• No known allergy to pomegranate juice
• More than 4 weeks since prior participation in another experimental study

Exclusion Criteria:

• nodal involvement
• evidence of metastatic disease
• prior hormonal therapy
• concurrent hormonal therapy for rising PSA levels after initial therapy for prostate cancer
• concurrent participation in another experimental study
• other concurrent systemic or local therapy for prostate cancer
• initiation or discontinuation of any new nutritional or dietary supplements during study participation