Do phytoestrogens reduce the risk of breast cancer and breast cancer recurrence? What clinicians need to know

Abstract

. Do phytoestrogens reduce the risk of breast cancer and breast cancer recurrence? What clinicians need to know. European journal of cancer (Oxford, England : 1990), 44(13), 1799 -1806 . DOI: 10.1016 /j.ejca.2008 Published in: European journal of cancer (Oxford, England : 1990) Queen's University Belfast -Research Portal: Link to publication record in Queen's University Belfast Research Portal General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. In this article, we present findings from human observational and intervention studies related to both isoflavone and lignan exposure and breast cancer risk and survival. In addition, the clinical implications of these findings are examined in the light of a growing dietary supplement market. An increasing number of breast cancer patients seek to take supplements together with their standard treatment in the hope that these will either prevent recurrence or treat their menopausal symptoms. Observational studies suggest a protective effect of isoflavones on breast cancer risk and the case may be similar for increasing lignan consumption although evidence so far is inconsistent. In contrast, short-term intervention studies suggest a possible stimulatory effect on breast tissue raising concerns of possible adverse effects in breast cancer patients. However, owing to the dearth of human studies investigating effects on breast cancer recurrence and survival the role of phytoestrogens remains unclear. So far, not enough clear evidence exists on which to base guidelines for clinical use, although raising patient awareness of the uncertain effect of phytoestrogens is recommended.

The DietCompLyf study: A prospective cohort study of breast cancer survival and phytoestrogen consumption

“…The biological complexity of phytoestrogens is well described [5]. Understanding the in vivo effects of phytoestrogens is complicated by different forms and quantities of intake and individual metabolic differences.…”

Significant changes in dietary intake and supplement use after breast cancer diagnosis in a UK multicentre study

“…This finding highlights the need to educate patients about the harmful effects of such products, providing guidance for supplements to avoid. As patients may not readily disclose information about supplement consumption to their clinician [43] and their habits may change periodically, it may be advisable for clinicians to regularly ask patients about their supplement use and suggest caution due to a lack of evidence of any beneficial effects [44]. At the same time, more research on the effects of oestrogenic and other supplements in breast cancer patients and tighter regulations on labelling are needed.…”

Serum enterolactone and postmenopausal breast cancer risk by estrogen, progesterone and herceptin 2 receptor status

“…[14][15][16][17][18][19][20][21] Two recently published metaanalyses (including our own) showed that high serum or urinary enterolactone levels were associated with a nonsignificant reduced postmenopausal breast cancer risk, whereas high consumption of dietary lignans was associated with a significant reduced postmenopausal breast cancer risk. 22,23 The objective of our study was to examine the association of the major serum enterolignan (enterolactone) with the risk of postmenopausal breast cancer in a large German study population with Western dietary habits. Additionally, we investigated whether this association differs by ER, progesterone receptor (PR) or herceptin receptor (HER2) status of the tumor.…”