Background: Sentinel lymph node (SLN) sampling is used to predict axillary lymph node (AxLN) metastasis in patients with breast carcinoma; AxLN sampling can be avoided in SLN-negative patients. Multistep sectioning and immunohistochemistry are reported to increase the sensitivity of micrometastasis detection. The authors used immunofluorescence (IF) staining with cytokeratin (CK) antibodies for intraoperative evaluation of touch imprints from multistep sections of SLNs.
Methods: A combined total of 150 SLNs from 69 patients who had breast carcinoma and underwent surgery were analyzed. SLNs were sectioned at 2 mm intervals, and touch imprints subsequently were prepared. After ethanol fixation, slides were incubated with fluorescein isothiocyanate-conjugated CK and propidium iodide and then subjected to microwave irradiation for 3 minutes. Finally, fluorescence microscopy was used to evaluate slides for the presence or absence of metastatic disease.
Results: Metastatic disease was identified in 36 (24.0%), 26 (17.3%), 32 (21.3%), and 31 (20.7%) of 150 lymph nodes using IF staining, Papanicolaou (Pap) staining, immunocytochemical (ICC) staining, and hematoxylin and eosin (H and E) staining, respectively. The sensitivities of IF, Pap, ICC, and H and E staining were 94.6%, 70.3%, 86.5%, and 83.8%, respectively. Except for IF staining (specificity, 99.1%), each method had a specificity of 100%. The accuracy rates for IF, Pap, ICC, and H and E staining were 98.0%, 92.7%, 96.7%, and 96.0%, respectively.
Conclusions: IF is a rapid, highly sensitive, and highly specific staining technique by which touch imprints can be used to intraoperatively evaluate SLNs in patients with breast carcinoma.
Copyright 2003 American Cancer Society.