Low-Fat Fish Oil Diet for Prostate Cancer Prevention
Condition: Prostate Cancer
MeSH terms: Prostatic Neoplasms
Study type: Interventional

Summary: 
      Studies on patterns of how many men get prostate cancer in other countries show that
      environment contributes to the high incidence of prostate cancer in the United States.
      Epidemiology studies suggest that this influence may be reduced by the diet of men at risk of
      getting prostate cancer. Although the exact nature of the effects of diet are not completely
      known, the amount of fat eaten appears to affect the number of men who get prostate cancer.
      The type of fat also seems to matter. Eating more of a type of fat called omega-3
      polyunsaturated fat is associated with decreased prostate cancer risk. Omega-3 fat comes from
      fish and is quite different from the type of fat from animals and vegetables (omega-6 fat).
      Because the exact mechanism of this reduction in prostate cancer risk is not known, no blood
      test indications, called markers, have been discovered that would show the effect working.

      Study doctors designed this study to try to find markers in the blood tests of men who have
      prostate cancer, and to find out if a diet supplemented with omega-3 type fat from fish oil
      helps reduce those markers, hence indicating that it helps reduce the cancer in these men.
      These men will be compared to men with prostate cancer whose diets do not contain the
      fish-oil fat.

      The men chosen will have prostate cancer and be scheduled for operations to have their
      prostate glands removed. They will be chosen randomly to be given the fish-oil diet or a
      regular Western diet for comparison for 4 to 8 weeks. Their blood will be checked at the
      beginning of the diet. After the 4-to-8-week period, they will have their operations. Their
      blood will be checked again and a sample of their removed prostate will be examined to tell
      if the diet had any effect on the cancer and its markers.
    

Detailed description: 
      1. To establish and validate intermediate biomarkers for prostate cancer prevention trials
           by conducting a dietary intervention trial of a low-fat diet with omega-3 fatty acid
           supplements in men undergoing radical prostatectomy. In initial trials it was feasible
           to intervene with diet and obtain tissue and serum for bioassay and biomarker
           development. This aim is to study the effect a low-fat, high omega-3 diet has on serum
           and tissue biomarkers from patients who have prostatectomies for prostate cancer.
           Ultimately, we hope to identify and validate intermediate markers of efficacy for
           large-scale dietary prevention trials.

        2. To establish and validate insulin growth factor-1 (IGF-1) and insulin growth factor
           binding proteins (IGFBP) as relevant intermediate biomarkers for prostate cancer
           prevention trials. IGF-1 is a peptide growth factor that is important to the growth and
           progression of prostate cancer. To our knowledge, no prospective dietary intervention
           studies have evaluated the effect of a low-fat diet with omega-3 fatty acid supplements
           on IGF-1 and IGFBPs, and their potential to serve as relevant intermediate markers for
           low-fat dietary intervention trials for prostate cancer prevention.

        3. To establish and validate serum and tissue fatty acids as relevant intermediate
           biomarkers for prostate cancer prevention trials. We will evaluate if men randomized to
           a low-fat, fish-oil-supplemented diet have increased serum ratios of omega-3:omega-6
           fatty acids compared with men randomized to a control Western diet before radical
           prostatectomy. We also will study if patients in the low-fat, fish oil arm have
           increased ratios of membrane omega-3:omega-6 fatty acids as well as decreased COX-2 and
           decreased PGE-2 levels in benign and malignant tissue and in visceral fat. If so, it
           will proved further evidence to support the potential of low-fat fish oil diets for
           prostate cancer prevention. If serum omega-3:omega-6 ratios correlate with changes in
           COX-2 and PGE-2 in tissues, then serum omea-3:omega-6 ratios may be useful for
           monitoring activity and efficacy of low-fat fish-oil-supplemented diets in future
           trials.
    

Intervention name(s): Fish Oil; Vitamin E supplement; Western Diet; Low-Fat Diet; Medical Examination; Dietary Interview; Blood Draw; Radical Prostatectomy
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement; Dietary Supplement; Other; Other; Other; Procedure
Intervention description(s): Subjects will be asked to take 10 grams of fish oil per day for 4 weeks.; Subjects will be asked to take 800 International Units per day of Vitamin E for 4 weeks.; Subjects will be provided with a standard western diet, food and beverages, to consume during their 4 week participation in this study.; Subjects will be provided with a low-fat diet (food and beverages) for their 4 week participation in this study.; Subjects will have a routine medical exam.; Subjects will meet with the study nutritionist and have their current diet evaluated. Subjects will also undergo a test (bioimpedance) to estimate their body fat, lean weight, and the rate at which their body burns fat.; 40 mL of blood will be drawn from subjects to measure PSA, fatty acids, insulin and various hormones.; Subjects will undergo a radical prostatectomy as part of their standard of care.
Intervention MeSH terms: Vitamin E
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic