title: The superparamagnetic iron oxide is equivalent to the Tc99 radiotracer method for identifying the sentinel lymph node in breast cancer.
abstract: BACKGROUND
  Preoperative injection of Tc99 is standardly performed before sentinel lymph node biopsy (SLN) for breast cancer. Multiple questions have arisen concerning appropriate technique for SLNBs including site of injection, timing and injection material. The aim of this study was to assess the concordance between a new method, superparamagnetic iron oxide (SPIO) and the Tc99 radiotracer to identify the SLN in early breast cancer.
  
  
  METHODS
  Between July 2013 and March 2014, 120 patients with clinically node negative early breast cancer were included in the study. Patients were injected the day before the radiotracer for lymphoscintigraphy and injected the SPIO subareolar intraoperatively. SLN was excised if it was radioactive, magnetic or palpable. Patients signed an inform consent.
  
  
  RESULTS
  There was no drainage by either technique in 2 patients, so this leaves 118 patients for further analysis. Detection rate by Tc 99 was successful in 113 (95.7%%) patients and by SPIO in 116 (98.3%). Concordance rates per patient between techniques was 98.2%. The SLN was positive in 36 (30%) patients. Of this, SLN positivity was detected by both techniques in 32 patients. Mean number of SLNs by 99Tc and SPIO were 1.9 and 2.21 respectively (p = 0.001).
  
  
  CONCLUSIONS
  Detection of SLNs with SPIO allows for easy identification of axillary nodes, at a frequency not inferior to the radiotracer. It is an oncologically safe procedure, facilitates patients and operative room management and can be used to reliably identify SLNs in breast cancer.
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain. Electronic address: irubio@vhio.net.
authors.forename: I T
authors.initials: IT
authors.lastname: Rubio
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Diaz-Botero
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Esgueva
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Rodriguez
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Cortadellas
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: O
authors.initials: O
authors.lastname: Cordoba
authors.affiliation: Breast Surgical Oncology Unit, Breast Cancer Center, Hospital Universitario Vall d'Hebron, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Espinosa-Bravo
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; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology* / Q000601:surgery; D018275:Carcinoma, Lobular / Q000473:pathology* / Q000601:surgery; D005260:Female; D005290:Ferric Compounds; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D061305:Lymphoscintigraphy / Q000379:methods; D060306:Magnetometry / Q000379:methods; D008408:Mastectomy / Q000379:methods; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013668:Technetium Tc 99m Aggregated Albumin
chemical_list: D005290:Ferric Compounds; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; C083602:technetium Tc 99m nanocolloid; C000499:ferric oxide
keywords: Breast cancer; Paramagnetic iron tracer; Sentinel node