Soy before diagnosis went with longer survival; soy after did not
Across 12 studies and 37,275 women with breast cancer, soy eaten before diagnosis went with 16 percent better overall survival. Three of the four estimates missed significance.
What the study found
Soy eaten before diagnosis tracked with survival; after, it did not
Across 12 studies covering 37,275 women with breast cancer, soy intake before diagnosis went with 16 percent better overall survival. Three of the four survival estimates in the analysis, including both for intake after diagnosis, did not reach significance.
The caveat · Nobody was assigned to eat soy
Every included study is observational with self-reported intake, so soy eaters may simply differ from other patients. The authors describe their own overall-survival finding as limited evidence and confine it to postmenopausal patients. The search stops in January 2018.