Non-sentinel lymph node analysis with one-step nucleic acid amplification in breast cancer patients

•One-step nucleic acid amplification (OSNA) examines lymph node metastasis.•Sentinel lymph node (SLN) biopsy is performed for breast cancer patient.•A whole-node analysis of both SLN and non-SLN using the OSNA method was performed.•Rates of positivity of non-SLN metastases in case of SLN metastasis were examined.•Rates of non-SLN metastases were same regardless of the copy number of SLN.

BackgroundOne-step nucleic acid amplification (OSNA) examines lymph node metastasis in a semiquantitative manner with molecular biology techniques. In this study, we conducted a whole-node analysis of non-sentinel lymph nodes (SLNs) using the OSNA method in SLN metastasis-positive breast cancer patients.MethodsWith the OSNA method, we compared the rates of positivity of non-SLN metastasis in cases with both SLN micro- and macrometastases.ResultsThe rates of non-SLN metastasis positivity in those with SLN micrometastasis and macrometastasis were 44% and 48%, respectively, and this difference was not significant. When the study of non-SLN metastasis positivity was focused only on macrometastases, the rates of non-SLN metastasis positivity in patients with SLN micrometastasis and macrometastasis were 19% and 22%, respectively, and there was no significant difference.ConclusionRegardless of the copy number of SLN metastases, non-SLN metastases were found in approximately half of the cases.