Background: Sentinel lymph node (SLN) biopsy is used as a staging procedure in early breast cancer, however, histology based intra-operative assessment of the SLN status has a low sensitivity. The one-step nucleic acid amplification (OSNA) method was developed to detect metastases by amplification of cytokeratin (CK) 19 mRNA. Experience with OSNA during a French multi-centric prospective study, as well as intra-operative clinical routine use, is reported.
Patients and methods: For the clinical study 80 SLNs from 46 patients were assessed. During routine use, the central slice of the SLN from 197 patients was investigated by permanent histology and the remainder was assessed by OSNA.
Results: During the clinical study, OSNA detected 15/17 metastases, including all the macrometastases, reaching a 96.3% concordance rate, 88.2% sensitivity and 98.4% specificity. During routine use, both OSNA and histology detected 25 patients with metastasis.
Conclusion: OSNA is an accurate tool for intra-operative assessment of SLN status and could reduce the need for second surgery.