Estudio del ganglio centinela en el cáncer de mama por el método OSNA (One-Step Nucleic Acid Amplification) tras neoadyuvancia en el Hospital Universitario de Navarra

Abstract

BackgroundSelective sentinel node (SN) biopsy is the standard technique for axillary staging in breast cancer (BC). There is no consensus on the use of OSNA (One-Step Acid Nucleic Amplification) method for SN in patients undergoing neoadjuvant treatment (NAT). We have studied the results obtained in our centre to justify the advantages of its implementation. Material and methods42 cases were selected from the group of 163 patients with BC treated with NAT, who underwent OSNA of the SN, obtaining a mean of 2.1 nodes per patient. We also analyzed cytokeratin 19 (CK19) expression, tumour grade, molecular phenotype and the degree of response to NAT in these patients. The SN were studied using the OSNA technique and non-sentinel nodes using the traditional method. ResultsTumour grade was 2-3 in 97.6% of cases, phenotype luminal A (17%), luminal B (38%), triple-negative (26.1%) and HER2 (19%). The response to NAT was complete in 59.5% of patients and CK19 expression was unchanged. The nodes studied were positive in 9 patients (21.4%) in whom lymphadenectomy was performed and only one case had a non-sentinel node involvement (2.3%). ConclusionsThe OSNA method for the study of SN after NAT is far superior to the traditional method as it: It allows intraoperative detection of isolated cell group and micrometastases not detectable with traditional methods, avoiding second interventions. It avoids false negatives when the whole SN is analyzed. It shows that CK19 expression is not altered by NAT.