title: Risk factors for non-sentinel lymph node metastases in patients with breast cancer. The outcome of a multi-institutional study.
abstract: BACKGROUND
  In this multi-institutional prospective study, we evaluated whether we could identify risk factors predictive for non-sentinel lymph node (non-SN) metastases in breast cancer patients with a positive sentinel lymph node (SN).
  
  
  METHODS
  In this multi-institutional study, 541 eligible breast cancer patients were included prospectively.
  
  
  RESULTS
  The occurrence of non-SN metastases was related to the size of the SN metastasis (P = .02), primary tumor size (P = .001), and lymphovascular invasion (P = .07). The adjusted odds ratio was 3.1 for SN micro-metastasis compared with SN isolated tumor cells, 4.0 for SN macro-metastasis versus SN isolated tumor cells, 3.1 for tumor size (>3.0 cm compared with </=3.0 cm), and 2.0 for lymphovascular invasion (yes versus no). There were no positive non-SNs when the primary tumor size was </=1.0 cm (n = 24) [95% confidence interval (95% CI) 0%-14.0%]. The proportion of positive non-SNs ranged in a prognostic logistic regression model from 9.7% (95% CI 4.0%-23.0%) for patients with SN isolated tumor cells, tumor size of 1.1-3.0 cm, and without vessel invasion, to 72.6% (95% CI 47.0%-89.0%) for patients with SN macro-metastasis, tumor size >3.0 cm, and with vessel invasion.
  
  
  CONCLUSIONS
  We identified three predictive factors for non-SN metastases in breast cancer patients with a positive SN: size of the SN metastasis; primary tumor size; and vessel invasion. We were not able to identify a specific group of patients with a positive SN in whom the risk for non-SN metastases was less than 5%.
authors.affiliation: Department of Surgery, Radboud University Nijmegen Medical Center (MC), Nijmegen, The Netherlands.
authors.forename: Marieke J
authors.initials: MJ
authors.lastname: Bolster
authors.forename: Petronella G M
authors.initials: PG
authors.lastname: Peer
authors.forename: Peter
authors.initials: P
authors.lastname: Bult
authors.forename: Frederik B J M
authors.initials: FB
authors.lastname: Thunnissen
authors.forename: René F M
authors.initials: RF
authors.lastname: Schapers
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Meijer
authors.forename: Luc J A
authors.initials: LJ
authors.lastname: Strobbe
authors.forename: Charles L H
authors.initials: CL
authors.lastname: van Berlo
authors.forename: Jean H G
authors.initials: JH
authors.lastname: Klinkenbijl
authors.forename: Louk V A M
authors.initials: LV
authors.lastname: Beex
authors.forename: Theo
authors.initials: T
authors.lastname: Wobbes
authors.forename: Vivianne C G
authors.initials: VC
authors.lastname: Tjan-Heijnen
mesh_terms: D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008875:Middle Aged; D012307:Risk Factors; D021701:Sentinel Lymph Node Biopsy