title: Factors influencing the number of sentinel lymph nodes identified in patients with breast cancer.
abstract: BACKGROUND
  Although the sentinel lymph node (SLN) is defined as the first node draining a tumor, multiple nodes are often identified. Few SLNs are required for adequate staging; removal of more may be unnecessary. The objective of this study was to determine factors influencing the number of SLN identified.
  
  
  METHODS
  The University of Louisville Breast Sentinel Lymph Node Study was used to determine correlates of identifying greater than 4 SLNs by using univariate and multivariate analyses.
  
  
  RESULTS
  An SLN was identified in 3,882 of 4,131 patients (94%). The median number of SLN identified was 2 (range 1-18); 90% had < or = 4 SLNs identified. Palpable tumors, surgeon inexperience, and dermal injection were associated with greater than 4 SLNs identified. All 3 of these factors remained significant on multivariate analysis.
  
  
  CONCLUSIONS
  Palpable tumors often have greater than 4 SLNs identified, and the use of intradermal injection increases this probability.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, University of Louisville, 315 East Broadway, Suite #312, Louisville, KY, USA. anees.chagpar@nortonhealthcare.org
authors.forename: Anees B
authors.initials: AB
authors.lastname: Chagpar
authors.forename: David J
authors.initials: DJ
authors.lastname: Carlson
authors.forename: Alison L
authors.initials: AL
authors.lastname: Laidley
authors.forename: Souzan E
authors.initials: SE
authors.lastname: El-Eid
authors.forename: Terre Q
authors.initials: TQ
authors.lastname: McGlothin
authors.forename: Robert D
authors.initials: RD
authors.lastname: Noyes
authors.forename: Phillip B
authors.initials: PB
authors.lastname: Ley
authors.forename: Todd M
authors.initials: TM
authors.lastname: Tuttle
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McMasters
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007271:Injections, Intradermal; D016015:Logistic Models; D008875:Middle Aged; D015999:Multivariate Analysis; D021701:Sentinel Lymph Node Biopsy / Q000379:methods / Q000592:standards