This randomized phase II trial will evaluate if a low omega-6, high omega-3 fat diet combined with fish oil has the potential to delay disease progression in patients with prostate cancer undergoing active surveillance.
PRIMARY OBJECTIVES: I. Determine if a 1-year low omega-6, high omega-3 fat diet combined with fish oil results in decreased prostate cancer Ki-67 index as compared to a control group in men on active surveillance. SECONDARY OBJECTIVES: I. Evaluate the effect of a low-fat (LF)/fish oil (FO) intervention on prostate biopsy tissue markers of progression, prostate biopsy pathologic features (Gleason grade, tumor volume ), prostate-specific antigen (PSA), and long-term clinical outcomes (clinical progression, prostate cancer therapies). II. Evaluate potential surrogate biomarkers of proliferation (red blood cell \[RBC\] membrane fatty acid analyses, ex-vivo bioassay). III. Determine if a correlation exists between free fatty acid receptor 4 (GPR120) levels and progression markers in response to the LF/FO intervention. IV. Evaluate effect of the intervention on the National Comprehension Cancer Network (NCCN) risk group V. Evaluate compliance with a 1-year + 2 year extension LF/FO intervention. VI. Evaluate safety of a 1-year + 2-year extension LF/FO intervention. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive no intervention. ARM II: Patients receive dietary counseling with a research dietitian weekly for 1 month and then monthly for 11 months. Patients are given guidelines with recommended meals to follow a high omega-3, low omega-6 diet comprising 30% kilocalories (Kcal) from fat, 15% Kcal from protein, and 65% Kcal from carbohydrates for 1 year. Patients also receive 4 fish oil capsules per day orally (PO) for 1 year. After completion of study, patients are followed up yearly for 15 years.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
107
Receive dietary counseling
Receive guidelines for low-fat diet
Given PO
Jonsson Comprehensive Cancer Center
Los Angeles, California, United States
Ki-67 index
The primary statistical analysis will be to compare the Ki67 index between the two intervention arms using a negative binomial mixed effects model
Time frame: 1 year
Composite measure: Prostate biopsy tissue markers of proliferation, cell cycle progression, and prostate biopsy pathologic features (Gleason grade, percent of cores with cancer, and percent of tissue with cancer)
Different types of regression models will be used to assess the influence of the intervention and clinical characteristics (ex. logistic regression, ordinal regression, Poisson regression instead of linear regression).
Time frame: 1 year
Serum PSA
Different types of regression models will be used to assess the influence of the intervention and clinical characteristics (ex. logistic regression, ordinal regression, Poisson regression instead of linear regression).
Time frame: Up to 1 year
Composite measure: Long-term clinical outcomes (clinical progression, prostate cancer therapies)
Different types of regression models will be used to assess the influence of the intervention and clinical characteristics (ex. logistic regression, ordinal regression, Poisson regression instead of linear regression).
Time frame: Up to 15 years
Composite measure: Potential surrogate biomarkers of proliferation (RBC membrane fatty acid analyses, ex-vivo bioassay)
Different types of regression models will be used to assess the influence of the intervention and clinical characteristics (ex. logistic regression, ordinal regression, Poisson regression instead of linear regression). Whether the omega-6/omega-3 ratio provides additional predictive information beyond group will be assessed by investigating whether it correlates with Ki-67 within each group.
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Correlative studies
Time frame: Up to 1 year
Correlation of GPR120 expression in peripheral blood mononuclear cells (PBMCs) and prostate biopsy tissue with immunostaining of Ki67 and Decipher Score
Linear regression will be used to correlate PBMC and biopsy GPR120 gene and protein expression to 1-year Ki-67 index and Decipher score . GPR120 gene and protein expression will be added to the linear regression for Ki-67 constructed with group and clinical/demographic covariates.
Time frame: Up to 1 year
Compliance, defined as having taken 80% or more of the daily fish oil throughout the trial determined based on pill count
Analysis of subject compliance to dietary regimen
Time frame: Up to 1 year
Incidence of adverse events graded according to National Cancer Institute Common Toxicity Criteria version 4.0
Measure of adverse events incidence
Time frame: Up to 1 year
Sample storage for future research
Urine, plasma and flash frozen prostate tissue will be stored for future research evaluating the effects of a LF/FO diet on prostate cancer progression.
Time frame: Up to 1 year