title: A Population-Based Study of the Effects of a Regional Guideline for Completion Axillary Lymph Node Dissection on Axillary Surgery in Patients with Breast Cancer.
abstract: Evidence from the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial suggests completion axillary lymph node dissection (cALND) after positive sentinel lymph node biopsy (+SLNB) does not improve outcomes in select patients, leading to practice variation. A multidisciplinary group of surgeons, oncologists, and pathologists developed a regional guideline for cALND which was disseminated in August 2012. We assessed the impact of Z0011 and the regional guideline on cALND rates.
  
  
  
  Consecutive invasive breast cancer cases undergoing SLNB were reviewed at 12 hospitals. Patient, tumor, and process measures were collected for three time periods: TP1, before publication of Z0011 (May 2009-August 2010); TP2, after publication of Z0011 (March 2011-June 2012); and TP3, after guideline dissemination (January 2013-April 2014). Cases were categorized by whether they met the guideline criteria for cALND (i.e. ≤50 years, mastectomy, T3 tumor, three or more positive sentinel lymph nodes [SLNs]) or not (e.g. age > 50 years, breast-conserving surgery, T1/T2 tumor, and one to two positive SLNs).
  
  
  
  The SLNB rate increased from 56 % (n = 620), to 70 % (n = 774), to 78 % (n = 844) in TP1, TP2, and TP3, respectively. Among cases not recommended for cALND using the guideline criteria, cALND rates decreased significantly over time (TP1, 71 %; TP2, 43 %; TP3, 17 %) [p < 0.001]. The cALND rate also decreased over time among cases recommended to have cALND using the guideline criteria (TP1, 92 %; TP2, 69 %; TP3, 58 %) [p < 0.001]. Based on multivariable analysis, age and nodal factors appeared to be significant factors for cALND decision making.
  
  
  
  Publication of ACOSOG Z0011 and regional guideline dissemination were associated with a marked decrease in cALND after +SLNB, even among several cases in which the guideline recommended cALND.
authors.affiliation: Department of Surgery, McMaster University, Hamilton, ON, Canada.
authors.forename: Miriam W
authors.initials: MW
authors.lastname: Tsao
authors.affiliation: Department of Surgery, McMaster University, Hamilton, ON, Canada.
authors.forename: Sylvie D
authors.initials: SD
authors.lastname: Cornacchi
authors.affiliation: Department of Surgery, McMaster University, Hamilton, ON, Canada.|Department of Surgical Oncology, Hamilton Health Sciences and Juravinski Hospital and Cancer Centre, Hamilton, ON, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Hodgson
authors.affiliation: Department of Surgery, McMaster University, Hamilton, ON, Canada.|Department of Surgical Oncology, Hamilton Health Sciences and Juravinski Hospital and Cancer Centre, Hamilton, ON, Canada.|Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada.
authors.forename: Marko
authors.initials: M
authors.lastname: Simunovic
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada.|Biostatistics Unit, St. Joseph's Healthcare, Hamilton, ON, Canada.
authors.forename: Lehana
authors.initials: L
authors.lastname: Thabane
authors.affiliation: Biostatistics Unit, St. Joseph's Healthcare, Hamilton, ON, Canada.
authors.forename: Ji
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: O'Brien
authors.affiliation: Department of Oncology, McMaster University, Hamilton, ON, Canada.
authors.forename: Barbara
authors.initials: B
authors.lastname: Strang
authors.affiliation: Department of Oncology, McMaster University, Hamilton, ON, Canada.
authors.forename: Som D
authors.initials: SD
authors.lastname: Mukherjee
authors.affiliation: Department of Surgery, McMaster University, Hamilton, ON, Canada. lovricsp@mcmaster.ca.|Department of Surgical Oncology, Hamilton Health Sciences and Juravinski Hospital and Cancer Centre, Hamilton, ON, Canada. lovricsp@mcmaster.ca.|Department of Surgery, St. Joseph's Healthcare, Hamilton, ON, Canada. lovricsp@mcmaster.ca.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lovrics
mesh_terms: D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D065186:Interrupted Time Series Analysis; D008197:Lymph Node Excision / Q000706:statistics & numerical data*; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D017410:Practice Guidelines as Topic; D012372:ROC Curve; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data*; D047368:Tumor Burden