RATIONALE: Eating a diet high in vegetables may lower the risk of some types of cancer. Brassica vegetables (such as cabbages, kale, broccoli, Brussels sprouts, and cauliflower) and indole-3-carbinol (a substance found in cruciferous vegetables) may help lower the risk of prostate cancer recurrence.

PURPOSE: This randomized clinical trial is studying the side effects and how well Brassica vegetables work compared with indole-3-carbinol in treating patients with PSA recurrence after surgery for prostate cancer.

OBJECTIVES:

• Determine the feasibility of Brassica vegetable intake and indole-3-carbinol supplement use in patients with prostate cancer with prostate-specific antigen (PSA) recurrence after prostatectomy.
• Identify adverse events in these patients.
• Quantify the effects of each intervention on PSA in these patients.

OUTLINE: Patients are stratified by pretreatment prostat-specific antigen (PSA) growth rate (low [0.00-0.15] vs medium [0.16-0.30] vs high [> 0.30]). They are randomized to 1 of 3 treatment arms, and randomization status to arms II and III is double-blinded.

• Arm I (Brassica vegetables): Patients consume Brassica vegetables at least 2 servings (½ cup/serving) daily for 6 months. Patients meet one-on-one with the study dietician, and are instructed on the potential health benefits of Brassica vegetables and purchase and preparation of the vegetables. Patients undergo telephone counseling periodically in months 1-5, to monitor their progress and identify barriers to adherence and to develop solutions to overcome these barriers.
• Arm II (Placebo): Patients receive oral placebo once daily for 6 months.
• Arm III (Indole-3-carbinol supplement): Patients receive oral indole-3-carbinol supplement (capsules) once daily for 6 months.

Blood and urine samples (for urinary isothiocyanate levels) are collected at baseline and at 2, 4, and 6 months. Patients complete questionnaires assessing demographics, family cancer history, and health history and measuring changes in medications, lifestyle, adverse events, and health. Medical records are reviewed for prostate cancer-related information, surgical dates, dose and type of radiation, and PSA history.

Inclusion Criteria:

• Diagnosis of prostate cancer with PSA recurrence after prostatectomy

  • PSA recurrence is defined as two consecutively rising PSA tests ≥ 8 weeks since the post-surgical nadir, with a minimal interval of 2 weeks between tests and at least 1 PSA test > 0.4 ng/mL

Exclusion Criteria:

• Life expectancy ≥ 9 months
• No predictors of poor adherence (e.g., erratic life-style, mental incompetence)

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

• No other concurrent Brassica vegetable consumption > 1 serving/day

• No other concurrent indole-3-carbinol supplements

• No endocrine or radiation treatment within past 4 weeks

• No other scheduled treatment during study intervention

• Concurrent prescription medications during the trial allowed

  • At least 2 weeks since prior and no concurrent vitamin or herbal supplement use

    • Patients refusing to stop non-study supplements will be asked to maintain constant use