Background: To validate the clinical value of the One-Step Nucleic Acid Amplification (OSNA) Breast Cancer System for the intraoperative detection of sentinel lymph node (SLN) metastases in early-stage breast cancer patients in a Chinese population, a prospective, multicenter trial, the China Breast Cancer Clinical Study Group (CBCSG)-001c trial, was conducted. The present study focused on the prospective comparison of the performance between OSNA and touch imprint cytology (TIC).
Methods: The retrieved SLNs were divided into sections. Alternate slices from the tissue blocks were subjected either to OSNA analysis or to postoperative histopathology evaluation through serial sectioning. TIC was performed on every sample surface of each tissue block and was used by the surgeon to determine whether to perform an immediate ALND.
Results: A total of 552 patients qualified for the analysis. The sensitivity, specificity, and overall accuracy of OSNA were 87.8%, 89.6%, and 88.4%, respectively, on a per-patient basis compared with those of TIC, which were 81.3%, 96.9%, and 92.0%, respectively. OSNA detected more micrometastasis-involved nodes than TIC (52.8% vs. 25.0%; p = 0.029) on a per-node basis. Tissue allocation bias (TAB) was the main cause of discordant results. The performance of TIC varied significantly among the institutes, while the performance of OSNA was steady.
Conclusions: Both OSNA and TIC can serve as qualified intraoperative assessments of SLNs. For institutes lacking the support of experienced cytopathologists, OSNA can be the first choice for the intraoperative assessment. In addition, OSNA can be applied as a complement to histopathology assessment. However, the results of the present study do not support the routine application of OSNA in the entire SLNs in place of pathology with serial sectioning.
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