title: Routine use of standard breast MRI compared to axillary ultrasound for differentiating between no, limited and advanced axillary nodal disease in newly diagnosed breast cancer patients.
abstract: OBJECTIVE
  To compare standard breast MRI to dedicated axillary ultrasound (with or without tissue sampling) for differentiating between no, limited and advanced axillary nodal disease in breast cancer patients.
  
  
  METHODS
  All patients who underwent breast MRI and dedicated axillary ultrasound between 2009 and 2014 were eligible. Exclusion criteria were recurrent disease, neoadjuvant systemic therapy and not receiving completion axillary lymph node dissection after positive sentinel lymph node biopsy (SLNB). Two radiologists independently reassessed all MRI exams. Axillary ultrasound findings were retrospectively collected. Probability of advanced axillary nodal disease (pN2-3) given clinically node negative (cN0) or limited (cN1) findings was calculated, with corresponding negative predictive value (NPV) to exclude pN2-3 and positive predictive value (PPV) to identify axillary nodal disease. Histopathology served as gold standard.
  
  
  RESULTS
  A total of 377 cases resulted in 81.4% no, 14.4% limited and 4.2% advanced axillary nodal disease at final histopathology. Probability of pN2-3 given cN0 for breast MRI and axillary ultrasound was 0.7-0.9% versus 1.5% and probability of pN2-3 given cN1 was 11.6-15.4% versus 29.0%. When cN1 on breast MRI was observed, PPV to identify positive axillary nodal disease was 50.7% and 59.0%.
  
  
  CONCLUSIONS
  Evaluation of axillary nodal status on standard breast MRI is comparable to dedicated axillary ultrasound in breast cancer patients. In patients who underwent preoperative standard breast MRI, axillary ultrasound is only required in case of suspicious nodal findings on MRI.
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands; GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, The Netherlands. Electronic address: Thiemovn@gmail.com.
authors.forename: T J A
authors.initials: TJA
authors.lastname: van Nijnatten
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: E H
authors.initials: EH
authors.lastname: Ploumen
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands; GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Catharina Hospital, Eindhoven, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: Schipper
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands; GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Goorts
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: E H
authors.initials: EH
authors.lastname: Andriessen
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Vanwetswinkel
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Schavemaker
authors.affiliation: Department of Epidemiology, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Nelemans
authors.affiliation: Department of Pathology, Zuyderland Hospital, Heerlen, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: de Vries
authors.affiliation: GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, The Netherlands; Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: R G H
authors.initials: RGH
authors.lastname: Beets-Tan
authors.affiliation: Department of Surgery, Maastricht University Medical Center+, Maastricht, The Netherlands; GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: Smidt
authors.affiliation: Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: M B I
authors.initials: MBI
authors.lastname: Lobbes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla / Q000000981:diagnostic imaging; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging; D018275:Carcinoma, Lobular / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D013667:Technetium; D016217:Ultrasonography, Mammary / Q000379:methods*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D013667:Technetium
keywords: Axilla; Breast cancer; Lymph nodes; Magnetic resonance imaging; Ultrasound