Plasma phytoestrogens and subsequent breast cancer risk.

TitlePlasma phytoestrogens and subsequent breast cancer risk.
Publication TypeJournal Article
Year of Publication2007
AuthorsVerheus, M, van Gils, CH, Keinan-Boker, L, Grace, PB, Bingham, SA, Peeters, PHM
JournalJ Clin Oncol
Volume25
Issue6
Pagination648-55
Date Published2007 Feb 20
ISSN1527-7755
KeywordsAge Distribution, Aged, Breast Neoplasms, Case-Control Studies, Cohort Studies, Confidence Intervals, Female, Follow-Up Studies, Genistein, Humans, Incidence, Middle Aged, Netherlands, Odds Ratio, Phytoestrogens, Postmenopause, Premenopause, Prospective Studies, Reference Values, Risk Assessment, Sensitivity and Specificity, Tumor Markers, Biological
Abstract

PURPOSE: Phytoestrogens are plant compounds that are structurally and functionally similar to mammalian estrogens. By competing for estrogen receptors, phytoestrogens possibly inhibit binding of the more potent endogenous estrogens and decrease their potential effects on breast cancer risk. We investigated the association between plasma phytoestrogen levels and breast cancer risk in a prospective manner.

PATIENTS AND METHODS: We performed a nested case-control study within the Prospect cohort, one of the two Dutch cohorts participating in the European Prospective Investigation into Cancer and Nutrition. A total of 383 women (87 pre- or perimenopausal women [mean age, 52 years] and 296 postmenopausal women [mean age, 59 years]) who developed breast cancer were selected as case subjects and were matched to 383 controls, on date of blood sampling. Plasma levels of isoflavones (daidzein, genistein, glycitein, O-desmethylangolensin, and equol) and lignans (enterodiol and enterolactone) were measured. The isotope dilution liquid chromatography/tandem mass-spectrometry method incorporating triply 13C-labeled standards was used for all analyses. Breast cancer odds ratios were calculated for tertiles of phytoestrogen plasma levels using conditional logistic regression analysis.

RESULTS: For genistein, the risk estimate for the highest versus the lowest tertile was 0.68 (95% CI, 0.47 to 0.98). Similar protective effects, although not statistically significant, were seen for the other isoflavones. Lignan levels did not appear to be related to breast cancer risk. Results were the same in pre- or perimenopausal women, and in postmenopausal women.

CONCLUSION: High genistein circulation levels are associated with reduced breast cancer risk in the Dutch population. No effects of lignans on breast cancer risk were observed.

DOI10.1200/JCO.2006.06.0244
Alternate JournalJ. Clin. Oncol.
Citation Key10.1200/JCO.2006.06.0244
PubMed ID17200150
Grant ListMC_U105630924 / / Medical Research Council / United Kingdom