Low-Grade Prostate Cancer 70 percent less likely to progress if good level of Omega-3 – June 2018

MP Omega-3 fatty acids and low-grade prostate cancer progression risk during active surveillance

To be presented June 26, 2018, 73 annual meeting of Canadian Urological Association.
Presenter, Vincent Fradet, Canada, Urologist oncologist, Clinician scientist, CHU de Québec, Laval University

Hanane Moussa1,4, Marie-Hélène Guertin1,4, Molière Nguile-Makao1, Janie Allaire2, Karine Robitaille1, Jean-François Pelletier1, Caroline Diorio4, Benoît Lamarche2, Pierre Julien3,4, Vincent Fradet1,2,4.
1 Oncology Axis, Centre de recherche du CHU de Québec - L’Hôtel-Dieu de Québec, Université Laval, Quebec City, QC, Canada;
2 Institute of Nutrition and Functional Foods (INAF), Université Laval , Quebec City, QC, Canada;
3 Endocrinology and Nephrology Axis, Centre de recherche du CHU de Québec , Université Laval , Quebec City, QC, Canada;
4 Faculty of Medicine , Université Laval, Quebec City, QC, Canada

Introduction: Prostate cancer (PCa) is the most frequently diagnosed cancer among Canadian men.1 Fat is an important dietary factor thought to impact PCa development and progression.2 Pre-clinical and clinical studies showed that intake of high omega-3 (Ω3) fatty acids (FA) has protective effects against PCa, likely via their anti-inflammatory properties.3,4 Here, we aimed at evaluating the associations between low-grade PCa progression and Ω3 status, which includes dietary intake, as well as Ω3 FA levels in circulation and in the prostatic tissue.

Methods: A total of 189 men diagnosed with low-grade PCa (Gleason score 6) who chose active surveillance were recruited in a phase 2b clinical trial. Eligible men (n=174) underwent a repeat prostate biopsy session 2-14 months after their initial PCa diagnosis. We conducted an observational study at this time point. For all men, FA intake was assessed using the food frequency questionnaire and their levels were measured in red blood cells and in prostate tissue using gaz chromatography. Logistic regression was used to evaluate the associations.

Results: At the first repeat biopsy session, PCa of 51 patients had progressed to a more aggressive form (Gleason score ≥7).
We found that high level of long-chain (LC) Ω3 in prostate tissue was associated with a reduced risk of PCa progression (odds ratio [OR] 0.30; 95% confidence interval [CI] 0.10-0.91; p=0.03).
Similar results were obtained with dietary LCΩ3 intake (OR 0.31; 95% CI 0.11- 0.86; p=0.02).
Also, we observed that a Ω6/Ω3 ratio measured in prostate tissue was positively associated with PCa progression risk (OR 2.91; 95% CI 1.04-8.17; p=0.04).

Conclusions: This study suggests that Ω3 FA, specifically LCΩ3, may be protective against low-risk PCa progression. In addition, results provide a rationale for LCn3-rich dietary intervention in men diagnosed with low-risk PCa, in order to reduce the risk of cancer progression.

References:

• [1] Fradet Y, Klotz L, Trachtenberg J, et al. The burden of prostate cancer in Canada. Can Urol Assoc J 2009;3:S92-100.
• [2] Gerber M. Omega-3 fatty acids and cancers: A systematic update review of epidemiological studies. Br J Nutr 2012;107Suppl2:S228-39. https://doi.org/10.1017/S0007114512001614
• [3] Demark-Wahnefried W, Polascik TJ, George SL, et al. Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men pre-surgery. Cancer Epidemiol Biomarkers Prev 2008;17:3577-87. https://doi.org/10.1158/1055-9965.EPI-08-0008
• [4] Fradet V, Cheng I, Casey G, et al. Dietary omega-3 fatty acids, cyclooxygenase-2 genetic variation, and aggressive prostate cancer risk. Clin Cancer Res 2009;15:2559-66. https://doi.org/10.1158/1078-0432.CCR-08-2503