The Effect of Eicosapentaenoic Acid on Prostate-specific Antigen

The "Study of EPA Effects on Prostate Cancer" (SEEPC) Group has been conducting a clinical trial with patients who underwent radical prostatectomy. The main purpose of the SEEPC is to evaluate whether eicosapentaenoic acid (EPA) prevents prostate cancer (PC) recurrence. As the surrogate marker of recurrence, the prostate-specific antigen (PSA) level was measured. However, if EPA affects the PSA values independently of PC, PSA may not be a good marker of recurrence in the event of EPA treatment. Thus, in the present study, whether EPA affected the PSA values was investigated using non-PC volunteers. Twenty men, of at least 50 years of age, were recruited, mostly from hospital staff. The volunteers were randomly allocated either to the EPA group or the control. The subjects in the EPA group were administered EPA-ethyl ester a dose of 2400 mg/day for 12 weeks, whereas the controls were administered none. Fasting blood samples were obtained before the start of EPA administration and 4 and 12 weeks later. The EPA concentrations in erythrocytes increased in all the subjects in the EPA group (174±96%) with no significant changes in the control group (8.5±14.0%). There were no significant differences between the two groups in the serum PSA levels, allowing the conclusion that the PSA is an appropriate surrogate marker of recurrence in prostate cancer.