Prostate cancer biochemical recurrence (BCR) occurs in 20-50% of patients following radical prostatectomy or radiotherapy. Due to significant risk of side effects and uncertainty about the benefits, physicians and patients are seeking alternatives to delay androgen deprivation therapy (ADT) for non-metastatic BCR. Long-chain omega-3 fatty acids (LCn3), mainly found in seafood and fatty fish, have beneficial effects against prostate cancer in pre-clinical experimental studies and randomized clinical trials of intermediate prostate cancer outcomes. The current observational evidence also supports testing LCn3 in prostate cancer patients. LCn3 have beneficial effects on inflammation, cardiovascular, psychological, and other outcomes, contrasting sharply with ADT-associated side effects.

Investigators propose to conduct a pilot randomized placebo-controlled trial to determine the effects over one year of an innovative LCn3 supplement (5g of omega-3-rich fish oil daily, including 4g of monoglycerides eicosapentaenoic acid (MAG-EPA)) in 40 men experiencing BCR or prostate cancer progression after a curative treatment.

This project proposes a simple intervention by dietary supplementation that could eventually help to prevent or delay ADT-related side effects and thus could contribute to diminish the heavy individual and societal burden of prostate cancer. The clinical data generated by this pilot trial will serve as basis for a larger-scale phase II clinical trial.

Inclusion Criteria:

• Patients must have a histologically or cytologically confirmed history of adenocarcinoma of the prostate.
• Patients must have a PSA failure defined as PSA of >= 0.5 ng/ml that has increased above nadir following radical prostatectomy (RP); or a PSA increase of 2.0 above post-therapy nadir after radiotherapy (RT); or a PSA increase between 0.05-0.49 ng/ml that has increased above nadir following RP. The maximal PSA value at enrolment must be <5.0 ng/mL after RP and <6 ng/mL after RT.
• PSA value must be increasing based on three consecutive measurements each separated by at least 4 weeks prior to enrolment to this study.
• Patients may have received any number of local therapies (RP, external beam RT or brachytherapy).
• Provide written informed consent.

Exclusion Criteria:

• Patients with evidence of metastatic disease.
• Patients who have received prior cytotoxic chemotherapy for recurrent disease.
• Patients currently receiving biological response modifiers, or corticosteroids.
• Uncontrolled intercurrent illness including, but not limited to, ongoing active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness or social situations that would limit compliance with study requirements.
• Use of omega-3 or any other dietary supplements for the previous 3 months and during study is not allowed.
• Known allergy to fish or shellfish or sunflower.