Soy and Cancer Survival

Soy foods may be safe, beneficial for breast cancer survivors.

USA Today (12/9, Szabo) reports that, according to a study published Dec. 9 in the Journal of the American Medical Association, "soy foods may be safe, and possibly even beneficial, for breast cancer survivors." Until now, "many breast cancer doctors have been cautious about recommending soy products -- such as soy milk, tofu, edamame, or miso soup -- because they contain plant estrogens. Most breast cancers are fueled by estrogen, which can make it risky to take additional hormones, such as for menopausal symptoms."
The Los Angeles Times (12/9, Roan) reports that researchers at Vanderbilt University "analyzed data from the Shanghai Breast Cancer Survival Study of 5,042" Chinese women "ages 20 to 75." The investigators found that "patients with the highest intake had a 29% lower risk of death during the study period and a 32% lower risk of breast cancer recurrence compared to patients with the lowest intake of soy foods," which "was measured by either soy protein or soy isoflavone intake."
Bloomberg News (12/9, Ostrow) reports, "The study, which followed women for an average of about four years, is the largest to examine the influence of soy intake on breast cancer survival and recurrence, the authors said. More than 192,000 women in the US will be diagnosed with breast cancer this year, according to the National Cancer Institute."
HealthDay (12/8, Gordon) reported, "What's more, the association between soy and a reduced risk of death held true even for women with estrogen receptor-positive cancers and women taking tamoxifen," the investigators found. In fact, the research team "found that soy actually reduces the availability of naturally occurring estrogen by binding to its receptors," having "a very similar effect to tamoxifen."
MedPage Today (12/8, Phend) noted that "the study was done in China, where soy intake tends to be higher than in the US and eaten in less processed forms." But, "while American women typically eat less than one-tenth as much soy as their counterparts in China, the results should be reassuring regardless of consumption, according to an accompanying editorial." The editorialists also "cautioned that any potential benefits cannot be extrapolated to dietary supplements containing soy," but said that "patients with breast cancer can be assured that enjoying a soy latte or indulging in pad thai with tofu causes no harm and, when consumed in plentiful amounts, may reduce risk of disease recurrence."

Citation: AMA