The objective of this study was to gain our initial experience in one-step nucleic acid amplification (OSNA) for detecting sentinel lymph node (SLN) metastasis as compared to standard pathological staging in patients with breast cancer. Fifteen patients with preoperatively confirmed early breast cancer eligible for breast‑saving therapy and sentinel lymph node biopsy (SLNB) were enrolled in the study. Lymphatic mapping and SLNs detection were performed through the magnetic method. Excised SLNs were intraoperatively examined through OSNA and frozen‑section methods. All lymph nodes were postoperatively examined through histopathology and immunohistochemistry. The results of latter methods were correlated. Our initial experience proved OSNA to be a sensitive and efficient alternative to intraoperative assessment of metastases in SLN in breast cancer patients. Moreover, the information obtained by the OSNA method provides the surgeon with the possibility of assessing a more accurate prognosis during the initial surgery (Tab. 3, Fig. 4, Ref. 36). Text in PDF www.elis.sk Keywords: breast cancer, metastases, surgery, sentinel nodes, OSNA.