Dietary intakes of total and specific lignans are associated with clinical breast tumor characteristics.

Dietary lignans may affect breast cancer by modifying tumor characteristics likely to affect prognosis. We investigated usual dietary intakes of total and specific lignans with tumor characteristics in 683 women with breast cancer and 611 healthy women without breast cancer enrolled in the Data Bank and BioRepository at Roswell Park Cancer Institute (RPCI). Clinicopathologic data were abstracted from the RPCI breast cancer database. Dietary lignan intakes were calculated from FFQ. OR and 95% CI were estimated with logistic regression adjusting for potential confounders and stratified by menopausal status. Women in the highest compared to the lowest tertile of total lignan intakes had a 40-50% lower odds of breast cancer regardless of menopausal status and substantially reduced odds of an invasive tumor, especially among premenopausal women [OR 0.48 (95% CI 0.26-0.86)]. Lignan intakes were inversely associated with odds of grade 3 tumors among premenopausal women. Lignan intakes were inversely associated with risk of estrogen receptor (ER) negative (ER(-)) breast cancer among premenopausal women [OR 0.16 (95% CI 0.03-0.44)] and particularly triple negative tumors [ER(-), progesterone receptor negative, HER2 negative; OR 0.16 (95% CI 0.04-0.62)]. There were significant differences in the contribution to these effects by specific lignans, especially matairesinol and lariciresinol. In summary, in this case-control study of dietary lignan intakes and breast cancer, we found that higher lignan intakes were associated with lower risks of breast cancer with more favorable prognostic characteristics. Future investigations are warranted to explore the strong associations observed with ER(-) cancer in premenopausal women.