title: Impact of the American College of Surgeons Oncology Group Z0011 Randomized Trial on the Number of Axillary Nodes Removed for Patients with Early-Stage Breast Cancer.
abstract: BACKGROUND
  The Z0011 trial showed similar outcomes between sentinel node biopsy (SNB) alone and axillary node dissection (ALND) for early-stage breast cancer, but few studies have examined Z0011's impact on practice patterns.
  
  
  METHODS
  Using the National Cancer Data Base, we examined use of SNB alone in patients who did and did not fulfill Z0011 eligibility criteria from 1998 to 2011. Because the National Cancer Data Base does not specifically identify SNB vs ALND, we categorized removal of ≤4 nodes as SNB only and ≥10 nodes as ALND.
  
  
  RESULTS
  Of 74,309 lumpectomy patients who fulfilled Z0011 criteria; 17,630 (23.7%) had a ≤4 nodes removed, 15,619 (21.0%) had 5 to 9 nodes removed, and 41,060 (55.3%) had ≥10 nodes removed. The proportion of lumpectomy patients receiving SNB increased from 6.1% in 1998 to 23.0% in 2009 to 56.0% in 2011 (p < 0.001). Independent predictors of ALND in lumpectomy patients were triple-negative tumors, younger than 50 years old, African-American race, size ≥3.0 cm, ≥2 positive nodes, invasive lobular carcinoma, grade III disease, and lymph node macrometastases. Patients outside of Z0011 criteria also underwent SNB alone: 54% of patients with tumors >5 cm, 52.5% who received no radiation therapy or accelerated partial breast irradiation, 35.9% with clinically positive nodes, 22.3% who underwent mastectomy, and 12.9% who had >3 tumor-positive nodes.
  
  
  CONCLUSIONS
  The use of SNB alone for patients fulfilling Z0011 criteria has increased substantially from 2009 to 2011. A considerable proportion of patients falling outside of Z0011 eligibility criteria were also treated with SNB alone.
authors.affiliation: Department of Surgery, Evanston Hospital, Evanston, IL; Department of Surgery, NorthShore University HealthSystem, University of Chicago, Pritzker School of Medicine, Chicago, IL. Electronic address: kyao@northshore.org.
authors.forename: Katharine
authors.initials: K
authors.lastname: Yao
authors.affiliation: Department of Surgery, Evanston Hospital, Evanston, IL.
authors.forename: Erik
authors.initials: E
authors.lastname: Liederbach
authors.affiliation: Department of Surgery, Evanston Hospital, Evanston, IL; Department of Surgery, NorthShore University HealthSystem, University of Chicago, Pritzker School of Medicine, Chicago, IL.
authors.forename: Catherine
authors.initials: C
authors.lastname: Pesce
authors.affiliation: Center for Biomedical Research Informatics, Evanston Hospital, Evanston, IL.
authors.forename: Chi-Hsiung
authors.initials: CH
authors.lastname: Wang
authors.affiliation: Department of Surgery, Evanston Hospital, Evanston, IL; Department of Surgery, NorthShore University HealthSystem, University of Chicago, Pritzker School of Medicine, Chicago, IL.
authors.forename: David J
authors.initials: DJ
authors.lastname: Winchester
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000601:surgery*; D018275:Carcinoma, Lobular / Q000473:pathology / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D019983:Guideline Adherence / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008197:Lymph Node Excision / Q000379:methods / Q000706:statistics & numerical data*; D015412:Mastectomy, Segmental; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D016032:Randomized Controlled Trials as Topic; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data; D014481:United States