title: Intraoperative sentinel lymph node assessment in breast cancer: a comparison of rapid diagnostic method based on CK19 mRNA expression and imprint cytology.
abstract: BACKGROUND
  Sentinel lymph node biopsy in breast cancer is a routine technique for staging the axilla. The two most common methods of intraoperative histopathological assessment, imprint cytology and frozen section, are hampered by poor sensitivity and lack standardized methodology. The one-step nuclei acid amplification (OSNA) assay is a rapid quantification of cytokeratin 19 mRNA. This prospective study compared an existing intraoperative imprint cytology protocol with the OSNA system.
  
  
  METHODS
  Of the 110 prospectively recruited patients, 98 met the inclusion criteria with a total of 170 lymph nodes. Intraoperative sentinel nodes were serially sectioned and imprints made of each cut surface for cytological assessment. Alternate slices were submitted for OSNA while the remaining slices were for final histopathological evaluation with six hematoxylin and eosin levels and one AE1/AE3 immunoperoxidase stain of each slice.
  
  
  RESULTS
  On histopathological analysis, 24.5% of patients (16.5% of nodes) had sentinel node metastases and 3.1% (2.4%) had isolated tumour cells. With isolated tumour cells cases taken as negative, the sensitivity of imprint cytology and OSNA compared with histopathology were 66.7% on patient basis (71.4% on per-node basis) and 95.8% (89.3%), respectively. One of 22 patients with macrometastases and two of three micrometastases were designated negative while five false-positive nodes were identified with OSNA, likely due to tissue allocation bias.
  
  
  CONCLUSIONS
  The OSNA assay is highly sensitive in comparison with imprint cytology and may be used effectively in the intraoperative setting. Clinical follow-up studies are warranted to further assess its use in routine practice.
authors.affiliation: Westmead Breast Cancer Institute, Westmead Hospital, Sydney, New South Wales, Australia; Department of Tissue Pathology and Diagnostic Oncology, Institute of Clinical Pathology and Medical Research, Westmead Hospital, Sydney, New South Wales, Australia; Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Nirmala
authors.initials: N
authors.lastname: Pathmanathan
authors.forename: Jasveen
authors.initials: J
authors.lastname: Renthawa
authors.forename: James R
authors.initials: JR
authors.lastname: French
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Edstrom-Elder
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Hall
authors.forename: Hema
authors.initials: H
authors.lastname: Mahajan
authors.forename: Christina
authors.initials: C
authors.lastname: Teh
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bilous
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D005260:Female; D005629:Frozen Sections; D006801:Humans; D007124:Immunoenzyme Techniques; D007430:Intraoperative Care; D053539:Keratin-19 / Q000032:analysis*; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis / Q000473:pathology; D008875:Middle Aged; D009367:Neoplasm Staging; D021141:Nucleic Acid Amplification Techniques; D011446:Prospective Studies; D012333:RNA, Messenger / Q000032:analysis*; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy
chemical_list: D053539:Keratin-19; D012333:RNA, Messenger
keywords: breast neoplasms; cancer, staging; keratin-19; nucleic acid amplification techniques; sentinel lymph node biopsy