Abstract P1-14-01: Feasibility study of moderate dose omega 3 fatty acid supplementation in premenopausal women at high risk for breast cancer considering future pregnancy

Abstract Background: 11% of women developing breast cancer are pre-menopausal women of childbearing potential under the age of 45. Pregnancy and breast feeding provide long term protection for breast cancer when they occur at an early age. The reasons for protection are poorly understood but likely involve both changes in the immune microenvironment and ductal and lobular epithelial differentiation. This pilot study is addressing a potential prevention strategy in a population otherwise excluded from breast cancer prevention trials and not eligible for standard of care chemoprevention. Methods: Eligible individuals included pre-menopausal women ages 21-40 that were considering future pregnancy and are at high risk for breast cancer based on family history, prior precancerous biopsy, or 5-year Gail model risk estimate of ≥ 1.7% or 10-year Tyrer-Cuzick risk of 2x population risk as listed in the model. Participants were enrolled and baseline tissue collection included random periareolar fine-needle aspiration (RPFNA) of breast, as well as collection of blood, urine and stool. Women were asked to take two capsules of Omega-3-Acid Ethyl Esters daily (a total of 750 mg DHA and 930 mg EPA) for six months. Post-intervention visit included repeat tissue collection. If women were pregnant at time of post-intervention visit, RPFNA was not done. Baseline and post-intervention DHA Food Frequency Questionnaire (FFQ) and the BCPT Questionnaire were administered. The intervention length was shortened for some participants due to the study ending. Objectives: 1) To determine feasibility of a breast cancer prevention intervention study in this cohort of pre-menopausal women at high risk for breast cancer and considering future pregnancy, 2) measure compliance with the omega-3 fatty acid supplement in this population, 3) identify novel biomarkers modulated by moderate dose omega-3 fatty acids in this population. Results: Ten women were successfully enrolled at an average rate of 1.5/month from a single center high risk breast clinic. Of the ten women enrolled, median age was 33 years (range 22-37, ±5.04 stdev), 70% married, 80% Non-Hispanic White, 10% of Ashkenazi Jewish descent and 40% reported having a genetic mutation. Feasibility was achieved with 80% (8 out of 10) of participants returning for post-intervention visit. Reasons given for discontinuation of study were (n=1) side effect from supplement (bloating) and (n=1) scheduling conflicts. Of the eight women who completed the off study visit, two chose not to undergo the off study RPFNA due to discomfort with initial procedure or time commitment. Self-reported pill count showed an average of three missed pills/month. Grade 1 related adverse events reported included odor, nausea and flatulence. Post-intervention, more participants reported diarrhea, vaginal discharge and bleeding, weight gain, general aches and dizziness on BCPT items compared to baseline. Change in benign breast tissue biomarkers will be reported including breast tissue cytomorphology, Ki67, fatty acid analysis and selected gene expression. Conclusion: It is feasible to recruit premenopausal women considering future pregnancy to a breast cancer prevention trial with a minimally invasive sampling procedure. Results from this trial will inform a larger randomized prevention trial. Citation Format: Lauren E Nye, Jennifer R Klemp, Kandy R Powers, Anne P O'Dea, Kendra A Cruz, Amy L Kreutzjans, Trina Metheny, Teresa A Phillips, Susan E Carlson, Bruce F Kimler, Carol J Fabian. Feasibility study of moderate dose omega 3 fatty acid supplementation in premenopausal women at high risk for breast cancer considering future pregnancy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-14-01.