One-step nucleic acid amplification assay (OSNA) for sentinel lymph node biopsy.

The one-step nucleic acid amplification assay (OSNA) has been developed for the intraoperative rapid detection of sentinel lymph node metastasis. Pooled analysis of recent studies comparing OSNA with pathology indicated that OSNA is as accurate as pathology (96.3 % concordance rate) and is useful for making the decision to omit axillary dissection for OSNA-negative patients (97.4 % negative predictive value). The advantage of OSNA over pathology is that the former allows the semiquantitative evaluation of total tumor volume in the node when a whole node is examined. OSNA is expected to be a powerful tool for the estimation of risk of non-sentinel lymph node metastasis and also patient prognosis, though further studies about this issue with larger numbers of patients is needed.