Evaluation of intraoperative touch imprint cytology on axillary sentinel lymph nodes in invasive breast carcinomas, a retrospective study of 1227 patients comparing sensitivity in the different tumor subtypes

BACKGROUND: Intraoperative evaluation of the axillary sentinel lymph node (SLN) in patients with breast carcinoma reduces the need of re-operations in cases where an axillary completion lymph node dissection (CLND) is indicated. Different methods have been used to determine the SLN status intraoperatively, e.g. frozen section histology (FS) and touch imprint cytology (TIC). The sensitivity of intraoperative TIC examination on SLN is not consistent between different studies and varies according to different tumor histologic subtypes, tumor size and the age of the patient. The aim of this study was to describe the specificity and sensitivity of TIC and to compare TIC sensitivity in the different histological subtypes of breast carcinoma. METHODS: A retrospective review was performed of 1227 consecutive clinically node negative breast cancer patients treated with sentinel lymph node biopsy (SLNB) with intraoperative TIC between the years 2003 and 2008. The SLN was bisected and stained using the May-Grünwald-Giemsa method and immunocytochemically with the antibody MNF-116. RESULTS: The overall sensitivity of the TIC test was 68.6% and the specificity was 99.8%. There was no statistically significant difference between the detection of SLN metastases from ductal carcinoma versus lobular carcinoma. The sensitivity improved over the period of the study. CONCLUSION: TIC is highly specific with an acceptable overall sensitivity. The sensitivity increased under the period of the study and it was higher in cases with larger size of the primary tumor. There was no difference in TIC sensitivity between the different histological subtypes.