Study on soy isoflavone consumption and risk of breast cancer and survival.

AIM Isoflavones in soy foods are part of a larger class of flayonoid compounds that have have been demonstrated to be potent dietary anti-cancer agents, and the effect of soy intake on the survival of ovarian cancer is conflicting. Therefore, we aimed to explore the whether soy intake is related to the risk of death of breast cancer. METHODS A prospective study was conducted. A total of 256 patients included in this study had breast cancer and were recruited between January 2004 and January 2006. All of them were followed up from since January 2011. A univariate Cox's regression analysis was used to assess the association between soy intake and survival. RESULTS The education level, menopausal status, ER/PR status and TNM stage were significant difference in the survival of breast cancer. The highest soy isoflavone was associated with a decreased death risk of breast cancer (OR=0.25, 95% CI=0.09-0.54). Moreover, the higher consumption of soy protein also presented a trend decreased breast cancer risk, and the highest consumption significantly reduced the cancer risk compared with the lowest consumption (OR=0.38, 95% CI=0.17-0.86). CONCLUSION The present study suggests soy intake is associated with a significant reduced death risk of breast cancer in Chinese population. Further large sample studies are warranted to confirm the inverse association of soy consumption and breast cancer survival by menopausal status.