title: Use of Gene Expression Profiling and Chemotherapy in Early-Stage Breast Cancer: A Study of Linked Electronic Medical Records, Cancer Registry Data, and Genomic Data Across Two Health Care Systems.
abstract: The 21-gene recurrence score (RS) identifies patients with breast cancer who derive little benefit from chemotherapy; it may reduce unwarranted variability in the use of chemotherapy. We tested whether the use of RS seems to guide chemotherapy receipt across different cancer care settings.
  
  
  
  We developed a retrospective cohort of patients with breast cancer by using electronic medical record data from Stanford University (hereafter University) and Palo Alto Medical Foundation (hereafter Community) linked with demographic and staging data from the California Cancer Registry and RS results from the testing laboratory (Genomic Health Inc., Redwood City, CA). Multivariable analysis was performed to identify predictors of RS and chemotherapy use.
  
  
  
  In all, 10,125 patients with breast cancer were diagnosed in the University or Community systems from 2005 to 2011; 2,418 (23.9%) met RS guidelines criteria, of whom 15.6% received RS. RS was less often used for patients with involved lymph nodes, higher tumor grade, and age < 40 or ≥ 65 years. Among RS recipients, chemotherapy receipt was associated with a higher score (intermediate v low: odds ratio, 3.66; 95% CI, 1.94 to 6.91). A total of 293 patients (10.6%) received care in both health care systems (hereafter dual use); although receipt of RS was associated with dual use (v University: odds ratio, 1.73; 95% CI, 1.18 to 2.55), there was no difference in use of chemotherapy after RS by health care setting.
  
  
  
  Although there was greater use of RS for patients who sought care in more than one health care setting, use of chemotherapy followed RS guidance in University and Community health care systems. These results suggest that precision medicine may help optimize cancer treatment across health care settings.
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Anosheh
authors.initials: A
authors.lastname: Afghahi
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Maya
authors.initials: M
authors.lastname: Mathur
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Thompson
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Aya
authors.initials: A
authors.lastname: Mitani
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Joseph
authors.initials: J
authors.lastname: Rigdon
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Manisha
authors.initials: M
authors.lastname: Desai
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Peter P
authors.initials: PP
authors.lastname: Yu
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Monique A
authors.initials: MA
authors.lastname: de Bruin
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Tina
authors.initials: T
authors.lastname: Seto
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Cliff
authors.initials: C
authors.lastname: Olson
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Pragati
authors.initials: P
authors.lastname: Kenkare
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Scarlett L
authors.initials: SL
authors.lastname: Gomez
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Amar K
authors.initials: AK
authors.lastname: Das
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Harold S
authors.initials: HS
authors.lastname: Luft
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: George W
authors.initials: GW
authors.lastname: Sledge
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH.
authors.forename: Amy P
authors.initials: AP
authors.lastname: Sing
authors.affiliation: Stanford University School of Medicine, Stanford; Palo Alto Medical Foundation Research Institute, Palo Alto; San Diego State University, San Diego; Cancer Prevention Institute of California, Fremont; Genomic Health Inc, Redwood City, CA; and Geisel School of Medicine, Lebanon, NH akurian@stanford.edu.
authors.forename: Allison W
authors.initials: AW
authors.lastname: Kurian
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D003695:Delivery of Health Care; D057286:Electronic Health Records; D005260:Female; D020869:Gene Expression Profiling; D023281:Genomics; D006801:Humans; D008875:Middle Aged; D018426:SEER Program