RT Journal Article
SR Electronic
T1 False negative rate for intraoperative sentinel lymph node frozen section in patients with breast cancer: a retrospective analysis of patients in a single Asian institution
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 536
OP 540
DO 10.1136/jclinpath-2014-202799
VO 68
IS 7
A1 Wong, Jolene
A1 Yong, Wei Sean
A1 Thike, Aye Aye
A1 Iqbal, Jabed
A1 Salahuddin, Ahmed Syed
A1 Ho, Gay Hui
A1 Madhukumar, Preetha
A1 Tan, Benita Kiat Tee
A1 Ong, Kong Wee
A1 Tan, Puay Hoon
YR 2015
UL http://jcp.bmj.com/content/68/7/536.abstract
AB Background and objective Intraoperative frozen section of the sentinel lymph node (SLN) in clinically node negative breast cancer patients detects metastatic disease and enables axillary lymph node dissection to be performed in the same operative setting. Internationally, the false negative rate (FNR) for SLN biopsy ranges from 5.5% to 43%. The size of SLN metastasis has been identified as a key factor affecting FNR. We review our institutional experience on the accuracy of intraoperative SLN biopsy.Methods Data were collected retrospectively from patients undergoing SLN biopsy performed at Singapore General Hospital. The SLN was identified using blue dye, radioisotope or both. Frozen section was performed intraoperatively. When SLN was positive for metastasis on frozen section, completion axillary clearance was performed. False negative cases were defined as patients in whom a negative frozen section result was obtained, whose final permanent paraffin section was positive. We determined the FNR of SLN frozen section and evaluated the factors associated with it.Results A total of 2202 SLN biopsies were performed between January 2005 and June 2012. There were 89 false negative cases, of which there were 23 (25.8%) cases of isolated tumour cells (ITCs), 49 (55.1%) cases of micrometastasis, and 17 (19.1%) cases of macrometastasis. The overall FNR was 13.5%. FNR was 79.3% in ITCs, 59.8% in micrometastasis, and 3.1% in macrometastatic disease. Non-ductal histological subtype, absence of lymphovascular invasion and the size of SLN metastasis were identified as significant independent factors associated with a higher FNR.Conclusions FNRin our institution is acceptable when compared to other large centres. Failure to detect metastasis in frozen section in more than half of our patients was due to ITCs and micrometastasis.