One-step nucleic acid amplification (OSNA) for the application of sentinel node concept in gastric cancer

This study was designed to apply safely the sentinel node navigation surgery (SNNS) to the malignancies, an accurate and prompt intraoperative diagnosis of SN is essential, and micrometastasis has been frequently missed by conventional frozen sections. Recently, a novel molecular-based rapid diagnosis for the lymph node (LN) metastases has been developed using (OSNA) in breast cancer, which takes approximately 30 min to obtain a final result. We evaluated the efficacy of OSNA in terms of the intraoperative diagnosis of LN metastasis in patients with gastric cancer.

A total of 162 LNs dissected from 32 patients with gastric cancer was included in this study; 45 LNs were pathologically diagnosed as metastatic LNs and 117 LNs were negative. The LNs were bisected; halves were examined with H&E stain, and the opposite halves were subjected to OSNA analyses of CK19 mRNA. The CK19 mRNA expression was examined in the positive or negative metastatic LNs, and the correlation between the tumor volume and CK19 mRNA expression in the metastatic LNs was examined.

The CK19 mRNA expressions in the positive metastatic LNs were significantly higher than those of negative LNs. When 250 copies/μl was set as a cutoff value, the concordance rate was 94.4%, the sensitivity was 88.9%, and the specificity was 96.6%. The OSNA expression was significantly correlated with the estimated tumor volumes in the metastatic LNs.

The OSNA method is feasible and acceptable for detecting LN metastases in patients with gastric cancer. This should be applied for the intraoperative diagnosis in the SN-navigation surgery in gastric cancer.