title: Intraoperative molecular assay for sentinel lymph node metastases in early stage breast cancer: a comparative analysis between one-step nucleic acid amplification whole node assay and routine frozen section histology.
abstract: BACKGROUND
  Conventional histopathological examination is limited in measuring accurate total metastatic volume in a lymph node. Recently, a molecular-based procedure to detect lymph node metastases, one-step nucleic acid amplification (OSNA) assay, has been developed. OSNA assay can assess a whole lymph node and yields semiquantitative results. The authors compared the performance in intraoperative detection of sentinel lymph node metastases with OSNA assay using a whole lymph node versus routine frozen section (FS) histology with a 2 mm-sectioned lymph node.
  
  
  METHODS
  Subjects comprised 531 consecutive patients diagnosed with OSNA assay and 618 consecutive patients diagnosed with FS histological examination. The authors compared the sentinel lymph node-positive rate between the OSNA and FS cohorts, and investigated characteristics of patients for whom OSNA could detect metastases but FS could not. OSNA (+) was defined as micrometastasis, and OSNA (++) and (+I) were defined as macrometastasis.
  
  
  RESULTS
  OSNA assay detected more cases of sentinel lymph node metastases than FS histology (OSNA 121 of 531, 22.8% vs FS 109 of 618, 17.6%; P = .036), particularly micrometastases (46 of 531, 8.7% vs 28 of 618, 4.5%; P = .0064). There was no difference in macrometastasis detection between OSNA and FS (75 of 531, 14.1% vs 81 of 618, 13.1%; P = .68). OSNA detected more metastases than FS in postmenopausal patients (77 of 302, 25.5% vs 43 of 351, 12.3%; P < .0001), and in tumors without fat invasion (23 of 156, 14.7% vs 6 of 151, 4.0%; P = .012) or lymphovascular invasion (67 of 395, 17.0% vs 45 of 458, 9.8%; P = .042).
  
  
  CONCLUSIONS
  Intraoperative OSNA assay detects more sentinel lymph node metastases, particularly micrometastases, than does FS histology. OSNA assay can also detect more metastases in postmenopausal patients or from less aggressive primary tumors compared with FS histology.
authors: Division of Pathology, the Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo, Japan. tomo.osako@jfcr.or.jp
authors: Tomo
authors: T
authors: Osako
authors: Takuji
authors: T
authors: Iwase
authors: Kiyomi
authors: K
authors: Kimura
authors: Kyoko
authors: K
authors: Yamashita
authors: Rie
authors: R
authors: Horii
authors: Akio
authors: A
authors: Yanagisawa
authors: Futoshi
authors: F
authors: Akiyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000235:genetics / Q000556:secondary; D018275:Carcinoma, Lobular / Q000175:diagnosis* / Q000235:genetics / Q000556:secondary; D015331:Cohort Studies; D004273:DNA, Neoplasm / Q000032:analysis* / Q000235:genetics; D005260:Female; D005629:Frozen Sections; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D021141:Nucleic Acid Amplification Techniques; D011379:Prognosis; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy
chemical_list: D004273:DNA, Neoplasm