Low-Fat Diet and/or Flaxseed in Preventing Prostate Cancer

OBJECTIVES:

Compare tumor proliferation in patients with newly diagnosed prostate cancer eating fat- and/or flaxseed-modified diets.
Compare differences in histopathological markers associated with prostate cancer (rates of apoptosis, extent of high-grade prostatic intraepithelial neoplasia) among patients in these diet groups.
Compare changes in serum prostate specific antigen among patients in these diet groups.
Compare changes in hormone-related factors (total serum testosterone and free androgen index, insulin-like growth factor [IGF], and IGF-binding protein-3) among patients in these diet groups.
Compare the effects of diet on nutritional biomarkers (levels of lignans in the urine and ejaculate, fatty acid profiles of erythrocytes and prostatic tissue) in these patients.
Determine associations between dietary modification and changes in dietary biomarkers, hormonal intermediates, and study endpoints in these patients.

OUTLINE: This is a randomized study. Patients are stratified according to Gleason score (less than 7 vs at least 7) and race (black vs non-black). Patients are randomized to 1 of 4 diet groups.

Arm I (Flaxseed-supplemented diet): Patients are instructed to incorporate ground flaxseed into their daily diets.
Arm II (Low-fat diet): Patients are instructed on ways to achieve a diet with no greater than 20% of total energy from dietary fat.
Arm III (Flaxseed-supplemented, low-fat diet): Patients are instructed as in arm I and arm II.
Arm IV (Control diet): Patients are contacted weekly, but do not receive dietary counseling until after surgery.

All patients ingest the diets for at least 3 weeks and complete diet diaries until surgery. After surgery, all patients receive dietary counseling.

PROJECTED ACCRUAL: A total of 160 patients (40 per treatment arm) will be accrued for this study.