Purpose: Jamaica has the highest incidence of prostate cancer in the world. Dietary fat is associated with prostate cancer. The Omega6 polyunsaturated fatty acids have been shown to stimulate prostate carcinogenesis and the Jamaican diet is rich in linoleic acid. We hypothesized positive correlations between Omega6 polyunsaturated fatty acid, prostate specific antigen and prostate biopsy pathology.
Materials and methods: A total of 148 men were enrolled in Kingston, Jamaica. Serum prostate specific antigen and erythrocyte membrane polyunsaturated fatty acids were analyzed. Men with prostate specific antigen 2.6 ng/ml or greater underwent biopsy. Histopathological and statistical analyses were performed on available data.
Results: Of the 54 men who underwent biopsy 24 had prostate cancer, 17 had a Gleason score of 7 or greater and 11 had a tumor volume of 50% or greater. There were significant positive correlations between linoleic acid and Gleason score (p = 0.009), and the linoleic acid-to-docosahexaenoic acid (Omega3) ratio and tumor volume (p = 0.03). There was a significant negative correlation between the arachidonic acid (Omega6)-to-docosapentanoic acid (Omega3) ratio and Gleason score (p = 0.04). Statistical correlations between prostate specific antigen and polyunsaturated fatty acids were inconsistent.
Conclusions: The positive correlations between linoleic acid and Gleason score, and the linoleic acid-to-docosahexaenoic acid ratio and tumor volume support studies showing that Omega6 polyunsaturated fatty acids stimulate and Omega3 polyunsaturated fatty acids inhibit prostate cancer growth. The negative correlation between the arachidonic acid-to-docosapentanoic acid ratio and Gleason score supports studies that demonstrate increased metabolism of arachidonic acid in prostate cancer to form carcinogenic metabolites, namely prostaglandin E2. Our findings support the association between dietary fatty acids and prostate cancer, and they warrant further dietary and tissue studies in high risk populations.