title: Positive effects of soy isoflavone food on survival of breast cancer patients in China.
abstract: OBJECTIVE
  Soy foods are the major source of isoflavones, which are believed to play important roles in genesis of breast cancer and its progression. We here conducted a prospective study to evaluate the association of soy isoflavone food consumption with breast cancer prognosis.
  
  
  METHODS
  A prospective study was performed from January 2004 and January 2006 in China. Trained interviewers conducted face-to-face interviews using a structured questionnaire to collect information on dietary habits and potential confounding factors. The relative risk [hazard ratio (HR)] and 95% CI were calculated from the Cox regression model for all significant predictors from cancer diagnosis to the endpoint of the study (event).
  
  
  RESULTS
  After a median follow up of 52.1 months (range, 9-60 months), a total of 79 breast cancer related deaths were recorded in our study, risk being inversely associated with a high intake of soy isoflavone. With an average intake of soy isoflavone above 17.3 mg/day, the mortality of breast cancer can be reduced by about 38-36%. We also found the decreased breast cancer death with high soy protein intake, with a HR (95% CI) of 0.71 (0.52-0.98). Stratified analysis with reference to the ER status, further demonstrated a better prognosis of ER positive breast cancer with a high intake of soy isoflavone (HR 0.59, 0.40-0.93).
  
  
  CONCLUSIONS
  Our study shows the soy food intake is associated with longer survival and low recurrence among breast cancer patients. A cohort study with a larger sample size and long term follow-up is now needed.
authors.affiliation: Department of General Surgery, The Affiliated Hospital of Inner Mongolia Medical College, Hohhot, China.
authors.forename: Ya-Feng
authors.initials: YF
authors.lastname: Zhang
authors.forename: Hong-Bin
authors.initials: HB
authors.lastname: Kang
authors.forename: Bi-Li
authors.initials: BL
authors.lastname: Li
authors.forename: Rui-Ming
authors.initials: RM
authors.lastname: Zhang
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000178:diet therapy* / Q000401:mortality*; D002681:China; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007529:Isoflavones / Q000627:therapeutic use*; D008875:Middle Aged; D017698:Postmenopause; D011379:Prognosis; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000378:metabolism; D045730:Soy Foods; D011795:Surveys and Questionnaires; D015996:Survival Rate
chemical_list: D007529:Isoflavones; D011960:Receptors, Estrogen