title: Oncologist and organizational factors associated with variation in breast cancer multigene testing.
abstract: OBJECTIVE
  Multigene testing for breast cancer recurrence risk became available in 2007, yet many eligible patients remain untested. This study evaluated variation in testing rates, and oncologist and organizational factors associated with variation, in a setting without financial influences on testing.
  
  
  METHODS
  We conducted a retrospective cohort study using electronic data and oncologist surveys within Kaiser Permanente Northern California, a large integrated health care system. Analyses included all 2974 test eligible patients from 2013 to 2015, 113 oncologists, and 15 practice groups. Receipt of multigene testing was evaluated with generalized linear mixed models.
  
  
  RESULTS
  Overall, 39% of eligible patients had multigene testing, but rates varied widely among practice groups, ranging from 24 to 48% after case mix adjustment. This 24% difference among practices was greater than the variation associated with most patient characteristics, including comorbidities and race/ethnicity, and similar to that associated with tumor size. Practice group and oncologist factors were statistically significant contributors to the variation in testing after adjusting for patient factors. Patients were more likely to be tested if they had a female oncologist (aOR 1.60, 95% CI 1.21-2.12) or were in a practice whose chief had a high testing rate (aOR 1.20, 95% CI 1.12-1.29 per 10% increase in the percent tested).
  
  
  CONCLUSIONS
  Oncologist and leadership practices play a key role in the variation in genomic test use for cancer recurrence risk even in a healthcare system without financial barriers to testing and could be a leverage point for implementing desired practice changes for new genomic advances.
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA. tracy.lieu@kp.org.
authors.forename: Tracy A
authors.identifier: http://orcid.org/0000-0002-3516-4617
authors.initials: TA
authors.lastname: Lieu
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: G Thomas
authors.initials: GT
authors.lastname: Ray
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Prausnitz
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Habel
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Stacey
authors.initials: S
authors.lastname: Alexeeff
authors.affiliation: Department of Oncology, Kaiser Permanente Oakland Medical Center, Oakland, CA, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Ramsey
authors.affiliation: University of Rochester, Rochester, NY, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Phelps
authors.affiliation: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA, 94612, USA.
authors.forename: Neetu
authors.initials: N
authors.lastname: Chawla
authors.affiliation: Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: C O'Neill
authors.affiliation: Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA.
authors.forename: Jeanne S
authors.initials: JS
authors.lastname: Mandelblatt
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics*; D002140:California; D019033:Delivery of Health Care, Integrated; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000235:genetics*; D000072103:Oncologists; D010818:Practice Patterns, Physicians'; D012189:Retrospective Studies
keywords: Genetic testing; Genomics; Practice change; Practice variation; Recurrence risk