RATIONALE: A low-fat, high-fiber diet that includes soy protein may prevent disease progression in patients with hormone-refractory prostate cancer. Nutrition counseling may help motivate patients to follow this diet.
PURPOSE: Randomized phase I trial to study the effectiveness of behavior-based dietary interventions, such as receiving nutrition counseling, in helping patients who have hormone-refractory prostate cancer follow a low-fat, high-fiber, soy-supplemented diet.
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| Enrollment: |
56 |
| Study Start Date: |
July 2002 |
| Study Completion Date: |
February 2006 |
| Primary Completion Date: |
February 2006 (Final data collection date for primary outcome measure) |
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Experimental: Arm I: Dietary Intervention
Nutritional counseling on a low-fat, high-fiber, soy supplemented diet and behavior-based activities, such as goal-setting, contracting, and stimulus control, once weekly for 6 weeks, every 3 weeks for 33 weeks, and then at weeks 44, 48, and 52.
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Behavioral: behavioral dietary intervention
Dietary Supplement: dietary intervention
Procedure: therapeutic dietary intervention
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No Intervention: Arm II: Observation
Observation every 6 weeks for 36 weeks and then every 8 weeks for 18 weeks.
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OBJECTIVES:
- Determine whether a behavior-based dietary intervention can motivate patients with hormone-refractory prostate cancer to adopt and maintain a dietary pattern that includes < 20% of energy from fat, > 25 g of fiber, and 80 g of soy protein powder.
- Compare bioavailable levels of testosterone in patients treated with a behavior-based dietary intervention vs observation only.
- Determine whether this dietary intervention decreases or stabilizes a rising serum prostate-specific antigen level in these patients.
- Determine whether this dietary intervention improves disease-specific survival, mediated by reduced bioavailable levels of testosterone, in these patients.
- Determine the impact of a positive intervention outcome on androgen receptors in patients treated with this dietary intervention.
OUTLINE: This is a randomized, controlled, pilot, multicenter study. Patients are randomized to 1 of 2 treatment arms.
All patients receive nutritional counseling on a healthy diet. Patients also keep a food diary during study participation.
- Arm I (dietary intervention): Patients receive dietary intervention comprising nutritional counseling on a low-fat, high-fiber, soy supplemented diet and behavior-based activities, such as goal-setting, contracting, and stimulus control, once weekly for 6 weeks, every 3 weeks for 33 weeks, and then at weeks 44, 48, and 52. Treatment continues in the absence of disease progression or unacceptable toxicity.
- Arm II (observation): Patients undergo observation every 6 weeks for 36 weeks and then every 8 weeks for 18 weeks.
PROJECTED ACCRUAL: A total of 92 patients (46 per treatment arm) will be accrued for this study.
