title: Postdiagnosis social networks and breast cancer mortality in the After Breast Cancer Pooling Project.
abstract: BACKGROUND
  Large social networks have been associated with better overall survival, though not consistently with breast cancer (BC)-specific outcomes. This study evaluated associations of postdiagnosis social networks and BC outcomes in a large cohort.
  
  
  METHODS
  Women from the After Breast Cancer Pooling Project (n = 9267) provided data on social networks within approximately 2 years of their diagnosis. A social network index was derived from information about the presence of a spouse/partner, religious ties, community ties, friendship ties, and numbers of living first-degree relatives. Cox models were used to evaluate associations, and a meta-analysis was used to determine whether effect estimates differed by cohort. Stratification by demographic, social, tumor, and treatment factors was performed.
  
  
  RESULTS
  There were 1448 recurrences and 1521 deaths (990 due to BC). Associations were similar in 3 of 4 cohorts. After covariate adjustments, socially isolated women (small networks) had higher risks of recurrence (hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.15-1.77), BC-specific mortality (HR, 1.64; 95% CI, 1.33-2.03), and total mortality (HR, 1.69; 95% CI, 1.43-1.99) than socially integrated women; associations were stronger in those with stage I/II cancer. In the fourth cohort, there were no significant associations with BC-specific outcomes. A lack of a spouse/partner (P = .02) and community ties (P = .04) predicted higher BC-specific mortality in older white women but not in other women. However, a lack of relatives (P = .02) and friendship ties (P = .01) predicted higher BC-specific mortality in nonwhite women only.
  
  
  CONCLUSIONS
  In a large pooled cohort, larger social networks were associated with better BC-specific and overall survival. Clinicians should assess social network information as a marker of prognosis because critical supports may differ with sociodemographic factors. Cancer 2017;123:1228-1237. © 2016 American Cancer Society.
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Candyce H
authors.initials: CH
authors.lastname: Kroenke
authors.affiliation: Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, Pennsylvania.
authors.forename: Yvonne L
authors.initials: YL
authors.lastname: Michael
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Poole
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Kwan
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Sarah
authors.initials: S
authors.lastname: Nechuta
authors.affiliation: San Diego Moores Cancer Center, University of California San Diego, La Jolla, California.
authors.forename: Eric
authors.initials: E
authors.lastname: Leas
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Bette J
authors.initials: BJ
authors.lastname: Caan
authors.affiliation: San Diego Moores Cancer Center, University of California San Diego, La Jolla, California.
authors.forename: John
authors.initials: J
authors.lastname: Pierce
authors.affiliation: Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.affiliation: Department of Cancer Prevention and Control, Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts.|Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Wendy Y
authors.initials: WY
authors.lastname: Chen
mesh_terms: D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009026:Mortality; D009367:Neoplasm Staging; D063868:Patient Outcome Assessment; D011159:Population Surveillance; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012944:Social Support; D012959:Socioeconomic Factors
chemical_list: D014408:Biomarkers, Tumor
keywords: breast cancer; mortality; social networks; social support; survival