title: Accuracy of frozen section analysis of sentinel lymph nodes for the detection of Asian breast cancer micrometastasis - experience from Pakistan.
abstract: BACKGROUND
  Intraoperative sentinel lymph node biopsy has now become the standard of care for patients with clinically node negative breast cancer for diagnosis and also in order to determine the need for immediate axillary clearance. Several large scale studies confirmed the diagnostic reliability of this method. However, micrometastases are frequently missed on frozen sections. Recent studies showed that both disease free interval and overall survival are significantly affected by the presence of micrometastatic disease. The aim of this study was to determine the sensitivity and specificity of intraoperative frozen section analysis of sentinel lymph nodes (SLNs) for the detection of breast cancer micrometastasis and to evaluate the status of non-sentinel lymph nodes (non-SLNs) in those patients subjected to further axillary sampling.
  
  
  METHODS
  We performed a retrospective study on 154 patients who underwent SLN biopsy from January 2008 till October 2011. The SLNs were sectioned at 2 mm intervals and submitted entirely for frozen sections. Three levels of each section submitted are examined and the results were compared with further levels on paraffin sections.
  
  
  RESULTS
  Overall 40% of patients (62/154) were found to be SLN positive on final (paraffin section) histology, out of which 44 demonstrated macrometastases (>2mm) and 18 micrometastases (<2mm). The overall sensitivity and specificity of frozen section analysis of SLN for the detection of macrometastasis was found to be 100% while those for micrometastasis were 33.3% and 100%, respectively. Moreover 20% of patients who had micrometastases in SLN had positive non-SLNs on final histology.
  
  
  CONCLUSIONS
  Frozen section analysis of SLNs lacks sufficient accuracy to rule out micrometastasis by current protocols. Therefore these need to be revised in order to pick up micrometastasis which appears to have clinical significance. We suggest that this can be achieved by examining more step sections of blocks.
authors.affiliation: Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan. doc_atif2005@yahoo.com
authors.forename: Atif Ali
authors.initials: AA
authors.lastname: Hashmi
authors.forename: Naveen
authors.initials: N
authors.lastname: Faridi
authors.forename: Amna
authors.initials: A
authors.lastname: Khurshid
authors.forename: Hanna
authors.initials: H
authors.lastname: Naqvi
authors.forename: Babar
authors.initials: B
authors.lastname: Malik
authors.forename: Faisal Riaz
authors.initials: FR
authors.lastname: Malik
authors.forename: Zubaida
authors.initials: Z
authors.lastname: Fida
authors.forename: Shafaq
authors.initials: S
authors.lastname: Mujtuba
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis*; D000328:Adult; D001943:Breast Neoplasms / Q000175:diagnosis*; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis*; D018275:Carcinoma, Lobular / Q000175:diagnosis*; D018276:Carcinoma, Medullary / Q000175:diagnosis*; D005260:Female; D005500:Follow-Up Studies; D005629:Frozen Sections; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D061206:Neoplasm Micrometastasis; D009367:Neoplasm Staging; D010154:Pakistan; D011379:Prognosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy; D013048:Specimen Handling