title: Associations between use of the 21-gene recurrence score assay and chemotherapy regimen selection in a statewide registry.
abstract: The 21-gene recurrence score (RS) assay predicts response to adjuvant chemotherapy in patients with early-stage, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative invasive breast cancer, but to the authors' knowledge, the role of the assay in guiding the selection of chemotherapy regimen has not been established. The current study was conducted to examine patterns of use of the RS assay for selecting chemotherapy regimens across a statewide registry from 2006 through 2013.
  
  
  
  Demographic, pathologic, and treatment data were abstracted from medical records for 16,666 women with breast cancer who were treated at 25 hospital systems across Michigan that were participating in the Michigan Breast Oncology Quality Initiative. Treatment patterns were examined based on the RS assay test result.
  
  
  
  Approximately 25% of patients with lymph node-negative disease who underwent testing with the RS assay and who were treated with chemotherapy received an anthracycline-based regimen, compared with 49% of patients with lymph node-negative disease who were treated with chemotherapy and who had not undergone testing with the RS assay. Of those patients with lymph node-positive disease who underwent testing with the RS assay and who received chemotherapy, 31% received an anthracycline-based regimen. In comparison, 71% of patients with lymph node-positive, chemotherapy-treated disease who did not undergo testing received an anthracycline. From 2006 through 2013, there was a statistically significant decrease in the use of anthracycline-containing regimens in both patients with lymph node-negative and lymph node-positive disease.
  
  
  
  Use of anthracycline-containing chemotherapy regimens in eligible patients appears to vary with use of the RS assay, despite the lack of evidence supporting use of the assay to guide regimen selection. Results of ongoing prospective trials should help to define the role of the RS assay in this setting. Cancer 2017;123:948-56. © 2016 American Cancer Society.
authors: Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
authors: N Lynn
authors: NL
authors: Henry
authors: Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan.
authors: Thomas M
authors: TM
authors: Braun
authors: Henry Ford Health Systems, Detroit, Michigan.
authors: Haythem Y
authors: HY
authors: Ali
authors: Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Khan
authors: K
authors: Munir
authors: Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Samuel M
authors: SM
authors: Silver
authors: Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan.|Barbara Ann Karmanos Cancer Institute, Detroit, Michigan.
authors: David H
authors: DH
authors: Gorski
authors: St. Joseph Mercy Hospital, Ann Arbor, Michigan.
authors: Tara M
authors: TM
authors: Breslin
authors: Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.|Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor, Michigan.
authors: Jennifer J
authors: JJ
authors: Griggs
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics*; D000066491:Clinical Decision-Making; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D005820:Genetic Testing; D006801:Humans; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000235:genetics*; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries
chemical_list: D014408:Biomarkers, Tumor
keywords: 21-gene recurrence score; anthracycline; breast cancer; chemotherapy; treatment regimen