In an article published online on September 6, 2011 in the Journal of Clinical Oncology, German researchers report that high serum levels of enterolactone, a biomarker of lignan intake, are associated with a significantly greater chance of surviving postmenopausal breast cancer in comparison with having low levels.
Lignans are phytoestrogen compounds found in whole-meal food products such as flax and other seeds, as well as in vegetables and wheat. These compounds are converted in the colon to enterolactone, which is then absorbed into the bloodstream.
For the study, serum enterolactone levels were measured in blood samples obtained between 2002 to 2005 from 1,140 postmenopausal women with breast cancer. Incidences of tumor metastasis or patient death were documented over a 6.1 median follow-up period.
One hundred sixty-two deaths occurred over follow-up. Women whose enterolactone levels were among the top 25 percent of participants had a 42 percent lower risk of dying over follow-up compared to those whose levels were among the lowest fourth. Subjects whose lignan intake was highest experienced a similarly reduced risk of metastasis. Further analysis determined a protective effect for enterolactone on estrogen receptor-negative tumors as opposed to those which were receptor-positive.
"We now have first clear evidence showing that lignans lower not only the risk of developing postmenopausal breast cancer, but also the mortality risk," stated lead researcher Jenny Chang-Claude of the German Cancer Research Center in Heidelberg. "The result was significant only for the group of tumors that have no receptor for the estrogen hormone. This gives reason to suspect that enterolactone protects from cancer not only by its hormone-like effect. In order to find out whether enterolactone also inhibits the aggressiveness of estrogen receptors in estrogen-positive tumors, we would need to expand this study to include much larger groups of women."
Follow this link to view the abstract of the study: http://jco.ascopubs.org/content/early/2011/09/06/JCO.2011.34.6478.abstract?sid=1e6005c8-b889-4e2b-aaac-948a4332459f.