title: A novel automated assay for the rapid identification of metastatic breast carcinoma in sentinel lymph nodes.
abstract: BACKGROUND
  The authors prospectively evaluated the performance of a proprietary molecular testing platform using one-step nucleic acid amplification (OSNA) for the detection of metastatic carcinoma in sentinel lymph nodes (SLNs) in a large multicenter trial and compared the OSNA results with the results from a detailed postoperative histopathologic evaluation (reference pathology) and from intraoperative imprint cytology (IC).
  
  
  METHODS
  In total, 1044 SLN samples from 496 patients at 11 clinical sites were analyzed. Alternate 1-mm sections were subjected to either detailed histopathologic evaluation with hematoxylin and eosin and pancytokeratin immunostaining or the OSNA Breast Cancer System, which was calibrated to detect tumor deposits >0.2 mm by measuring cytokeratin 19 messenger RNA. At 7 sites, IC was performed before permanent section. The OSNA results were classified as negative (<250 copies/μL), micrometastases (from ≥250 to <5000 copies/μL), or macrometastases (≥5000 copies/μL).
  
  
  RESULTS
  The sensitivity and specificity of the OSNA breast cancer system compared with reference pathology were 77.5% (95% confidence interval, 69.7%-84.2%) and 95.8% (95% confidence interval, 94.3%-97.0%), respectively, before discordant case analyses (DCA). Sensitivity and specificity after DCA were 82.7% and 97.7%, and final concordance was 95.8%. Performance for invasive lobular carcinoma demonstrated 88.2% sensitivity (95% confidence interval, 63.6%-98.5%) and 98.5% specificity (95% confidence interval, 92%-100%). The sensitivity of OSNA was significantly better than that of IC (80% vs 63%; P = .0229).
  
  
  CONCLUSIONS
  The OSNA breast cancer system proved to be highly accurate for the detection of metastatic breast cancer in axillary SLNs. Sensitivity was comparable to that predicted for conventional postoperative histologic examination at 2-mm intervals and was significantly more sensitive than IC. Automation, semiquantitative results enabling the differentiation of macrometastasis and micrometastasis, and rapid results render the assay suitable for intraoperative and/or permanent evaluation of SLNs.
authors.affiliation: Department of Surgery, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Sheldon
authors.initials: S
authors.lastname: Feldman
authors.forename: Savitri
authors.initials: S
authors.lastname: Krishnamurthy
authors.forename: William
authors.initials: W
authors.lastname: Gillanders
authors.forename: Mark
authors.initials: M
authors.lastname: Gittleman
authors.forename: Peter D
authors.initials: PD
authors.lastname: Beitsch
authors.forename: Peter R
authors.initials: PR
authors.lastname: Young
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Streck
authors.forename: Pat W
authors.initials: PW
authors.lastname: Whitworth
authors.forename: Edward A
authors.initials: EA
authors.lastname: Levine
authors.forename: Susan
authors.initials: S
authors.lastname: Boolbol
authors.forename: Linda K
authors.initials: LK
authors.lastname: Han
authors.forename: Robert
authors.initials: R
authors.lastname: Hermann
authors.forename: Dave S B
authors.initials: DS
authors.lastname: Hoon
authors.forename: Armando E
authors.initials: AE
authors.lastname: Giuliano
authors.forename: Funda
authors.initials: F
authors.lastname: Meric-Bernstam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy