title: Predicting the status of the nonsentinel axillary nodes: a multicenter study.
abstract: BACKGROUND
  Sentinel lymph node (SLN) biopsy is a minimally invasive procedure that provides accurate nodal staging information. The need for completion axillary dissection after finding a positive SLN for breast cancer has been questioned.
  
  
  OBJECTIVE
  The presence of nonsentinel node (NSN) metastases in the axillary dissection specimen correlates with tumor size, the number of SLNs removed, and the number of positive SLNs.
  
  
  METHODS
  Prospective, multi-institutional study.
  
  
  METHODS
  The University of Louisville Breast Cancer Sentinel Lymph Node Study is a nationwide study involving 148 surgeons. All patients underwent SLN biopsy, followed by level I/II axillary dissection. All SLNs were evaluated histologically at a minimum of 2-mm intervals. Immunohistochemical analysis using antibodies for cytokeratin was performed at the discretion of each participating institution. All NSNs were evaluated by routine histologic examination.
  
  
  RESULTS
  An SLN was identified in 1268 (90%) of 1415 patients. Increasing tumor size was significantly correlated with increasing likelihood of positive NSNs: T1a, 14%; T1b, 22%; T1c, 30%; T2, 45%; and T3, 57% (P =.002, chi(2) test). The presence of positive NSNs was not significantly associated with the number of SLNs removed. Patients with more than 1 positive SLN were more likely to have positive NSNs than those with only 1 positive SLN (50% vs 32%; P<.001, chi(2) test). Increasing tumor size and the presence of multiple positive SLNs were also associated with the presence 4 or more positive axillary nodes. Multivariate analysis confirmed that tumor size and the number of positive SLNs were independent factors predicting the presence of positive NSNs.
  
  
  CONCLUSIONS
  The likelihood of positive NSNs correlates with increasing tumor size and the presence of multiple positive SLNs. However, even patients with small primary tumors have a substantial risk of residual axillary nodal disease after SLN biopsy. These data will be helpful in counseling patients regarding the need for completion axillary dissection after a positive SLN is identified.
authors.affiliation: J. Graham Brown Cancer Center, University of Louisville, 529 S Jackson St, Louisville, KY 40202, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Wong
authors.forename: M J
authors.initials: MJ
authors.lastname: Edwards
authors.forename: C
authors.initials: C
authors.lastname: Chao
authors.forename: T M
authors.initials: TM
authors.lastname: Tuttle
authors.forename: R D
authors.initials: RD
authors.lastname: Noyes
authors.forename: C
authors.initials: C
authors.lastname: Woo
authors.forename: P B
authors.initials: PB
authors.lastname: Cerrito
authors.forename: K M
authors.initials: KM
authors.lastname: McMasters
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D011237:Predictive Value of Tests; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy