title: Is Routine Axillary Imaging Necessary in Clinically Node-Negative Patients Undergoing Neoadjuvant Chemotherapy?
abstract: BACKGROUND
  The National Comprehensive Cancer Network guidelines recommend axillary imaging prior to neoadjuvant chemotherapy (NAC) in breast cancer patients who are clinically node negative (cN0) by physical examination. However, the benefit of this approach remains uncertain. The purpose of this study was to determine whether abnormal axillary imaging pre-NAC predicts nodal metastases post-NAC (ypN+) in cN0 patients.
  
  
  METHODS
  cN0 patients undergoing NAC followed by axillary surgery were identified. Rates of ypN+ were compared among patients with abnormal pre-treatment axillary imaging vs. normal or no pre-treatment imaging using Fisher's exact test.
  
  
  RESULTS
  From May 2008 to March 2016, 402 eligible cN0 patients were identified. The median age of the patients was 49.5 years, and the median tumor size was 4 cm. Of these patients, 38% were estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-), 30% were HER2+ , and 32% were triple negative. All had pre-NAC mammograms, 40% axillary ultrasound, 83% MRI, and 51% PET. Abnormal nodes on imaging were seen in 208 patients (52%); 128 had pre-NAC node biopsy, and 75 were positive. Overall, 28% of the patients (n = 111) were ypN+ post-NAC. Although the incidence of ypN+ was significantly higher in patients with abnormal nodes on pre-NAC imaging (p = 0.001), 54% did not require axillary lymph node dissection (ALND) post-NAC. Among the patients with normal nodes on pre-NAC imaging, 20% were ypN+ post-NAC.
  
  
  CONCLUSIONS
  Half of patients with abnormal nodes on pre-NAC imaging did not require ALND post-NAC, while 20% of those with normal pre-NAC nodes had disease post-NAC, indicating that in cN0 patients already selected for NAC, axillary imaging pre-NAC does not predict the need for axillary surgery post-NAC with sufficient accuracy to be clinically useful.
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. barrioa@mskcc.org.
authors.forename: Andrea V
authors.initials: AV
authors.lastname: Barrio
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Anita
authors.initials: A
authors.lastname: Mamtani
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Eaton
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Brennan
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Stempel
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Morrow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001706:Biopsy; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D010808:Physical Examination; D049268:Positron-Emission Tomography; D017410:Practice Guidelines as Topic; D014463:Ultrasonography; D055815:Young Adult