title: Adoption of gene expression profile testing and association with use of chemotherapy among women with breast cancer.
abstract: OBJECTIVE
  Gene expression profile (GEP) testing is a relatively new technology that offers the potential of personalized medicine to patients, yet little is known about its adoption into routine practice. One of the first commercially available GEP tests, a 21-gene profile, was developed to estimate the benefit of adjuvant chemotherapy for hormone receptor-positive breast cancer (HR-positive BC).
  
  
  METHODS
  By using a prospective registry data set outlining the routine care provided to women diagnosed from 2006 to 2008 with HR-positive BC at 17 comprehensive and community-based cancer centers, we assessed GEP test adoption and the association between testing and chemotherapy use.
  
  
  RESULTS
  Of 7,375 women, 20.4% had GEP testing and 50.2% received chemotherapy. Over time, testing increased (14.7% in 2006 to 27.5% in 2008; P < .01) and use of chemotherapy decreased (53.9% in 2006 to 47.0% in 2008; P < .01). Characteristics independently associated with lower odds of testing included African American versus white race (odds ratio [OR], 0.70; 95% CI, 0.54 to 0.92) and high school or less versus more than high school education (OR, 0.63; 95% CI, 0.52 to 0.76). Overall, testing was associated with lower odds of chemotherapy use (OR, 0.70; 95% CI, 0.62 to 0.80). Stratified analyses demonstrated that for small, node-negative cancers, testing was associated with higher odds of chemotherapy use (OR, 11.13; 95% CI, 5.39 to 22.99), whereas for node-positive and large node-negative cancers, testing was associated with lower odds of chemotherapy use (OR, 0.11; 95% CI, 0.07 to 0.17).
  
  
  CONCLUSIONS
  There has been a progressive increase in use of this GEP test and an associated shift in the characteristics of and overall reduction in the proportion of women with HR-positive BC receiving adjuvant chemotherapy.
authors.affiliation: Center for Outcomes and Policy Research, Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA 02215, USA. michael_hassett@dfci.harvard.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hassett
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Silver
authors.forename: Melissa E
authors.initials: ME
authors.lastname: Hughes
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Blayney
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Edge
authors.forename: James G
authors.initials: JG
authors.lastname: Herman
authors.forename: Clifford A
authors.initials: CA
authors.lastname: Hudis
authors.forename: P Kelly
authors.initials: PK
authors.lastname: Marcom
authors.forename: Jane E
authors.initials: JE
authors.lastname: Pettinga
authors.forename: David
authors.initials: D
authors.lastname: Share
authors.forename: Richard
authors.initials: R
authors.lastname: Theriault
authors.forename: Yu-Ning
authors.initials: YN
authors.lastname: Wong
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Vandergrift
authors.forename: Joyce C
authors.initials: JC
authors.lastname: Niland
authors.forename: Jane C
authors.initials: JC
authors.lastname: Weeks
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D044383:Black People; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D017024:Chemotherapy, Adjuvant; D005260:Female; D020869:Gene Expression Profiling / Q000706:statistics & numerical data*; D054625:Healthcare Disparities; D006801:Humans; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000235:genetics; D011960:Receptors, Estrogen / Q000096:biosynthesis; D013997:Time Factors; D044465:White People; D055815:Young Adult; D001741:Black or African American
chemical_list: D011960:Receptors, Estrogen