Breast cancer patients and survivors can safely consume moderate amounts of soy foods, according to scientists from the American Institute for Cancer Research (AICR).
There is plenty of solid research, that for breast cancer patients and survivors, eating moderate amounts of soy doesn’t increase a woman’s risk for breast cancer. Clinical trials consistently show that soy isoflavone intake does not adversely affect markers of breast cancer risk, including mammographic density and cell proliferation. Furthermore, epidemiologic studies involving over 11,000 women from the USA and China show that postdiagnosis soy intake statistically significantly reduces recurrence and improves survival.
A dietician from AICR further explains in this recent video: http://www.aicr.org/enews/2016/05-may/enews-soy-and-cancer-risk.html