Plasma phospholipid fatty acids and prostate cancer risk in the SELECT trial - Abstract

Background: Studies of dietary ω-3 fatty acid intake and prostate cancer risk are inconsistent; however, recent large prospective studies have found increased risk of prostate cancer among men with high blood concentrations of long-chain ω-3 polyunsaturated fatty acids ([LCω-3PUFA] 20:5ω3; 22:5ω3; 22:6ω3]. This case-cohort study examines associations between plasma phospholipid fatty acids and prostate cancer risk among participants in the Selenium and Vitamin E Cancer Prevention Trial.

Methods: Case subjects were 834 men diagnosed with prostate cancer, of which 156 had high-grade cancer. The subcohort consisted of 1393 men selected randomly at baseline and from within strata frequency matched to case subjects on age and race. Proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for associations between fatty acids and prostate cancer risk overall and by grade. All statistical tests were two-sided.

Results: Compared with men in the lowest quartiles of LCω-3PUFA, men in the highest quartile had increased risks for low-grade (HR = 1.44, 95% CI = 1.08 to 1.93), high-grade (HR = 1.71, 95% CI = 1.00 to 2.94), and total prostate cancer (HR = 1.43, 95% CI = 1.09 to 1.88). Associations were similar for individual long-chain ω-3 fatty acids. Higher linoleic acid (ω-6) was associated with reduced risks of low-grade (HR = 0.75, 95% CI = 0.56 to 0.99) and total prostate cancer (HR = 0.77, 95% CI = 0.59 to 1.01); however, there was no dose response.

Conclusions: This study confirms previous reports of increased prostate cancer risk among men with high blood concentrations of LCω-3PUFA. The consistency of these findings suggests that these fatty acids are involved in prostate tumorigenesis. Recommendations to increase LCω-3PUFA intake should consider its potential risks.

Written by:
Brasky TM, Darke AK, Song X, Tangen CM, Goodman PJ, Thompson IM, Meyskens FL Jr, Goodman GE, Minasian LM, Parnes HL, Klein EA, Kristal AR   Are you the author?
Department of Internal Medicine, Division of Cancer Prevention and Control, The Ohio State University College of Medicine, Columbus, OH (TMB); Cancer Prevention Program (TMB, XS, GEG, ARK) and SWOG Statistical Center (AKD, CMT, PJG), Fred Hutchinson Cancer Research Center, Seattle, WA; Department of Urology, University of Texas-San Antonio Health Science Center, San Antonio, TX (IMT); Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA (FLM); Department of Environmental Health (GEG) and Department of Epidemiology (ARK), University of Washington, Seattle, WA; Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD (LMM, HLP); Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH (EAK)

Reference: J Natl Cancer Inst. 2013 Jul 10. (Epub ahead of print)
doi: 10.1093/jnci/djt174

PubMed Abstract
PMID: 23843441