title: Comparison of the sentinel node procedure between patients with multifocal and unifocal breast cancer in the EORTC 10981-22023 AMAROS Trial: identification rate and nodal outcome.
abstract: BACKGROUND
  Multifocal breast cancer is associated with a higher risk of nodal involvement compared to unifocal breast cancer and the drainage pattern from multifocal localisations may be different. For this reason, the value of the sentinel node biopsy (SNB) procedure for this indication is debated. The aim of the current analysis was to evaluate the sentinel node identification rate and nodal involvement in patients with a multifocal tumour in the EORTC 10981-22023 AMAROS trial.
  
  
  METHODS
  From the first 4000 registered patients, 342 were identified with a multifocal tumour on histological examination and compared to a randomly selected control group of 684 patients with a unifocal tumour. The outcome of the SNB was assessed.
  
  
  RESULTS
  The sentinel node was identified in 96% of the patients with a multifocal tumour and in 98% of those with unifocal disease. In the multifocal group, 51% had a metastasis in the sentinel node compared to 28% in the unifocal group; and further nodal involvement after a positive sentinel node was found in 40% (38/95) and 39% (39/101) respectively.
  
  
  CONCLUSIONS
  In this prospective international multicentre study, the 96% detection rate indicates that the SNB procedure can be highly effective in patients with a multifocal tumour. Though the tumour-positive rate of the sentinel node was twice as high in the multifocal group compared to the unifocal group, further nodal involvement after a positive sentinel node was similar in both groups. This suggests that the SNB procedure is safe in patients with multifocal breast cancer.
authors.affiliation: Department of Surgical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Mila
authors.initials: M
authors.lastname: Donker
authors.affiliation: Department of Surgical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Marieke E
authors.initials: ME
authors.lastname: Straver
authors.affiliation: Department of Radiation Oncology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Geertjan
authors.initials: G
authors.lastname: van Tienhoven
authors.affiliation: Department of Surgery, University Medical Centre, Leiden, The Netherlands.
authors.forename: Cornelis J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Department of Surgery, Cardiff University, Cardiff, Wales, United Kingdom.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mansel
authors.affiliation: European Organisation for Research and Treatment of Cancer, Brussels, Belgium.
authors.forename: Saskia
authors.initials: S
authors.lastname: Litière
authors.affiliation: European Organisation for Research and Treatment of Cancer, Brussels, Belgium.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Werutsky
authors.affiliation: European Organisation for Research and Treatment of Cancer, Brussels, Belgium.
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: Duez
authors.affiliation: Breast Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Orzalesi
authors.affiliation: Department of Surgery, Gelre Hospital, Apeldoorn, The Netherlands.
authors.forename: Willem H
authors.initials: WH
authors.lastname: Bouma
authors.affiliation: Department of Surgery, Nij Smellinghe Hospital, Drachten, The Netherlands.
authors.forename: Huub
authors.initials: H
authors.lastname: van der Mijle
authors.affiliation: Department of Surgery, Catharina Hospital, Eindhoven, The Netherlands.
authors.forename: Grard A P
authors.initials: GA
authors.lastname: Nieuwenhuijzen
authors.affiliation: Department of Surgery, Amstelland Hospital, Amstelveen, The Netherlands.
authors.forename: Sanne C
authors.initials: SC
authors.lastname: Veltkamp
authors.affiliation: Institute for Radiation Oncology Arnhem, Arnhem, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Helen Westenberg
authors.affiliation: Department of Surgical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. Electronic address: e.rutgers@nki.nl.
authors.forename: Emiel J T
authors.initials: EJ
authors.lastname: Rutgers
mesh_terms: D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D016896:Treatment Outcome