Administration of omega-3 fatty acids and Raloxifene to women at high risk of breast cancer: interim feasibility and biomarkers analysis from a clinical trial

Abstract

Background/objectives: The antiestrogen, Raloxifene (Ral) is an effective breast cancer chemopreventive agent. Omega-3 fatty acids (n-3FA) may inhibit mammary carcinogenesis. On the basis of their mechanisms of action, we test the hypothesis that a combination of n-3FA and Ral may be superior in reducing select biomarkers of breast cancer risk in women.

Subjects/methods: Postmenopausal women at increased risk for breast cancer (breast density ≥ 25%) were randomized to: (1) no intervention; (2) Ral 60 mg; (3) Ral 30 mg; (4) n-3FA (Lovaza) 4 g and (5) Lovaza 4 g+Ral 30 mg for 2 years. Reduction in breast density is the primary end point of the study. We report preliminary data on feasibility, compliance and changes in secondary end points related to IGF-I signaling, estrogen metabolism, oxidative stress and inflammation in the first group of 46 women who completed 1 year of the study.

Results: All interventions were well tolerated with excellent compliance (96 ± 1% overall) by pill count and also supported by the expected rise in both serum n-3FA and n-3FA/Omega-6 fatty acids (n-6FA) ratio in women randomized to groups 4 and 5 (P<0.05). Lovaza decreased serum triglycerides and increased high-density lipoprotein (HDL) cholesterol compared with control (P<0.05 for both). Ral reduced serum IGF-1 in a dose-dependent manner (P<0.05) while Lovaza did not. Lovaza had no effect on IGF-1 or IGFBP-3. None of the other biomarkers were affected by our treatment.

Conclusion: The combination of Lovaza and Ral is a feasible strategy that may be recommended in future breast cancer chemoprevention trials.